BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Integrable models with staggered disposition of R-matrices:Applica
tion to the Hall Effect
DTSTART;VALUE=DATE-TIME:20040122T100000Z
DTEND;VALUE=DATE-TIME:20040122T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0414@ictp.it
DESCRIPTION:ABSTRACT:\nA brief review of the Algebraic Bethe Ansatz (ABA)
technique and\nthe application to integrable models with staggered dispos
ition of \nR-matrices will be presented.\nA set of integrable ladder model
s based on this generalization of ABA\nwill be formulated.\nThe motivation
for consideration of integrable models with staggered\ndisposition of R-m
atrices comes from the phenomenological \nChalker-Coddington (CC) model of
edge excitations in quantum Hall effect\, \nresponsible for plateau-plate
au transitions. We present the Action \nformulation of the CC model and av
erage the Landauer resistance over U(1) phase \ndisorder. It appears\, tha
t the resultant model is integrable since \ncorresponding Yang-Baxter equa
tions are satisfied.\n\n//indico.ictp.it/event/a0414/
LOCATION:ICTP MB-2-239
URL://indico.ictp.it/event/a0414/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dynamics of spherical minority game
DTSTART;VALUE=DATE-TIME:20040126T100000Z
DTEND;VALUE=DATE-TIME:20040126T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0418@ictp.it
DESCRIPTION:Abstract: The dynamics of a spherical version of the batch min
ority game (MG) with random external information will be discussed. After
an introduction to the generating functional analysis of MGs and a discus
sion of the currently available dynamical approximations for the MG's key
observable\, the market volatility and for price return autocorrelations\,
we present a spherical version of the batch MG. This model is designed t
o be exactly solvable\, but we find that it still displays a non-trivial p
hase diagram. In contrast to standard MG versions\, we can calculate the
volatility exactly. Our study reveals similarities between the spherical
and the conventional MG\, but also intriguing differences.\n\n//indico.ict
p.it/event/a0418/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0418/
END:VEVENT
BEGIN:VEVENT
SUMMARY:TRIGGERING THE SELF-ASSEMBLY OF Au-C HYBRID NANOWIRES
DTSTART;VALUE=DATE-TIME:20040127T123000Z
DTEND;VALUE=DATE-TIME:20040127T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0420@ictp.it
DESCRIPTION:Abstract:\nHelical gold nanowires were experimentally found [1
] and their atomic\nstructure theoretically explained [2] very recently.\n
Below certain critical radius\, they were also found to spontaneously thin
\ndown to monatomic gold wires\, before final breaking.\nEven though the m
easured structure of the helical nanowires can be well\nunderstood within
ab-initio density functional theory (DFT) [2]\, at this\nlevel of descript
ion the simplest wires --the monatomic ones-- present\na puzzle:\nDFT the
oretical predictions of their stability-threshold-distances are far\ntoo s
hort compared to experimental measurements [3].\nSeveral attempts in order
to explain what is the origin of these\ndiscrepancies seem to point out t
he role of light weight impurity\natoms as the most likely factor.\nThe pr
esence of some impurity atoms\, such as C or S\, could distort easily\nthe
distances in the monatomic wires while remaining undetected to the\nexper
imental techniques [4-6].\nAn open question remains to be answered: what a
re the mechanisms that\npromote the formation of these hybrid nanowires?.\
nIn the present work\, the formation of a hybrid monatomic nanowire is\nsi
mulated via ab-initio DFT calculations.\nThe starting point is a short hel
ical gold nanowire with a single C atom\napproaching its surface.\nThe sim
ulation shows that at 400 K\, the C atom strongly binds to the wire\nand d
ives-in very rapidly. In the process\, the local structure undergoes\nnoti
ceable changes leading to a $sp^3$ coordination of the carbon atom\nwith f
our surrounding Au atoms.\nThe Mulliken population analysis\, computed for
this configuration\, reveals\nthat the C atom has withdrawn electrons fro
m the metallic environment\,\nacquiring a charge of about 0.6 $e$.\nUpon f
urther stretching\, the helical wires would eventually break and the C\nat
om becomes a key factor in the formation of the final hybrid monatomic wir
e.\nThe final structure\, before rupture\, is a 9-atoms-long monatomic wir
e\nthat connects to one of the tips via a the C atom\, that became\n$sp^3$
-coordinated with four Au neighbors.\n\n1.\\\\\, Y. Kondo and K. Takayanag
i\, Science\, {\\\\bf 289}\, 606\, (2000).\\\\\\\\\n2.\\\\\, E. Tosatti\,
S. Prestipino\, S. Kostlmeier\, A. Dal Corso\,\nand F. D. Di Tolla\, Scien
ce {\\\\bf 291}\, 288\, (2001).\\\\\\\\\n3.\\\\\, J. A. Torres\, E. Tosatt
i\, A. Dal Corso\, F. Ercolessi\, J. Kohanoff\,\nF. D. Di Tolla\, and J.M.
Soler\, Surf. Sci. Lett. {\\\\bf 426}\, L441 (1999).\\\\\\\\\n4.\\\\\, Da
niel Kr\\\\\\"uger\, Harald Fuchs\, Roger Rousseau\, Dominik Marx\,\nand M
ichele Parrinello\, Phys. Rev. Lett. {\\\\bf 89}\, 186402 (2002). \\\\\\\
\\n5.\\\\\, Sergio B. Legoas\, Douglas S. Galv\\\\\\"ao\, Varlei Rodrigues
\,\nand Daniel Ugarte\, Phys. Rev. Lett. {\\\\bf 88}\, 076105 (2002). \\\\
\\\\\n6.\\\\\, F. D. Novaes\, A. J. R. da Silva\, E. Z. da Silva\, and A.
Fazzio\,\nPhys. Rev. Lett. {\\\\bf 90}\, 036101\, (2003).\\\\\\\\\n\n//ind
ico.ictp.it/event/a0420/
LOCATION:ICTP MB-2-239
URL://indico.ictp.it/event/a0420/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Integrable models with staggered disposition of R-matrices:Applica
tion to the Hall Effect. II Part
DTSTART;VALUE=DATE-TIME:20040129T100000Z
DTEND;VALUE=DATE-TIME:20040129T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0422@ictp.it
DESCRIPTION:ABSTRACT:\nI will review the Chalker-Coddington (CC) model of
edge excitations in the quantum Hall effect\, responsible for plateau-plat
eau transitions. The\nAction formulation of the CC model and the average o
f the Landauer \nresistance over U(1) phase disorder will be presented. It
appears\, that \nthe resultant model is integrable since corresponding Ya
ng-Baxter \nequations are satisfied.\n\n//indico.ictp.it/event/a0422/
LOCATION:ICTP MB-2-239
URL://indico.ictp.it/event/a0422/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Integrable and Conformal Twisted Boundary Conditions of Lattice Mo
dels
DTSTART;VALUE=DATE-TIME:20040130T100000Z
DTEND;VALUE=DATE-TIME:20040130T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0419@ictp.it
DESCRIPTION:Abstract:\nIn this seminar\, I will talk about the integrable
lattice realizations of\nconformal twisted boundary conditions for $sl(2)$
unitary minimal models.\nThe conformal field theories are realized as the
continuum scaling limit\nof critical $A$-$D$-$E$ lattice models with posi
tive spectral parameter.\nThese integrable seam boundary conditions are as
sociated with the nodes of\nOcneanu quantum graph. The talk is at introduc
tary level.\n\n//indico.ictp.it/event/a0419/
LOCATION:ICTP MB-2-239
URL://indico.ictp.it/event/a0419/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Adsorption of organic molecules on semiconductor surfaces from fir
st principles: 3-pyrroline (C4H7N) and ethanol (C2H6O) on Si(100)
DTSTART;VALUE=DATE-TIME:20040203T123000Z
DTEND;VALUE=DATE-TIME:20040203T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0427@ictp.it
DESCRIPTION://indico.ictp.it/event/a0427/
LOCATION:ICTP MB-2-239
URL://indico.ictp.it/event/a0427/
END:VEVENT
BEGIN:VEVENT
SUMMARY:2D massless boson\, quantum sine-Gordon model and bosonization: E
lementary introduction - Part I
DTSTART;VALUE=DATE-TIME:20040205T100000Z
DTEND;VALUE=DATE-TIME:20040205T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0428@ictp.it
DESCRIPTION:ABSTRACT: These lectures are complementary to the introduction
to Conformal Field Theory given recently by Marina Huerta. Their goal is
to show how main ideas and mathematical structures of the formal CFT appro
ach show up in a simple and well-known example -- the 2D Gaussian model (
free massless boson). We will also consider a typical deformation of this
theory\, the 2D sine-Gordon model\, that displays a topological (Berezinsk
ii-Kosterlitz-Thouless) transition. Questions related to fermion-boson dem
ocracy will be finally discussed.\n\n//indico.ictp.it/event/a0428/
LOCATION:ICTP MB-2-239
URL://indico.ictp.it/event/a0428/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Properties of Large Organic Molecules at Metal Surfaces by STM
DTSTART;VALUE=DATE-TIME:20040210T123000Z
DTEND;VALUE=DATE-TIME:20040210T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0436@ictp.it
DESCRIPTION://indico.ictp.it/event/a0436/
LOCATION:ICTP MB-2-239
URL://indico.ictp.it/event/a0436/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Self-organized Critical Network Dynamics
DTSTART;VALUE=DATE-TIME:20040211T150000Z
DTEND;VALUE=DATE-TIME:20040211T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0433@ictp.it
DESCRIPTION:Abstract: Networks are a general framework by which we can des
cribe a large class of many-body systems of interacting elements. We will
propose a model that describes in a stylized way how local breakdowns due
for example to congestion problems may shape the structure of a network.\n
The model converges to a self-organized critical stationary state in which
the network structure results as a consequence of avalanches of rewiring
processes. Depending on the model's specification\, we obtain either singl
e scale or scale-free networks. We characterize in detail the relation bet
ween the statistical properties of the network and the nature of the criti
cal state\, by computing the critical exponents. The model also displays a
non-trivial\, sudden\, collapse to a complete network.\n\n//indico.ictp.i
t/event/a0433/
LOCATION:ICTP MB-2-239
URL://indico.ictp.it/event/a0433/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Large Effects of interactions and different geometries on conducta
nces of quantum wires: the ring and stub systems
DTSTART;VALUE=DATE-TIME:20040212T100000Z
DTEND;VALUE=DATE-TIME:20040212T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0439@ictp.it
DESCRIPTION:ABSTRACT: We examine the effect of interactions between the el
ectrons on the\nLandauer-B\\\\\\"uttiker conductances of some systems of q
uantum wires with\ndifferent geometries. The systems include a wire with a
stub in the\nmiddle\, and a wire containing a ring which can enclose a ma
gnetic flux.\nThe electrons in each of the wires is taken to be weakly int
eracting\,\nand scattering matrices are introduced at all the junctions pr
esent in\nthe systems. Using a renormalization group method developed rece
ntly\, we\ncompute the conductances of these systems as functions of the t
emperature\nand the wire lengths. We present results for high\, intermedia
te and low\ntemperatures which correspond respectively to the thermal cohe
rence length\nbeing smaller than\, comparable to and larger than the small
est wire length\nin the different systems\, i.e.\, the length of the stub
or each arm of the\nring. The renormalization group procedure and the form
ulae used to compute\nthe conductances are different in the three regimes.
Our results show that\nthe Landauer-B\\\\\\"uttiker conductances of vario
us systems of experimental\ninterest depend on the temperature and lengths
in a non-trivial way when\ninteractions are taken into account.\n\n//indi
co.ictp.it/event/a0439/
LOCATION:ICTP MB-2-239
URL://indico.ictp.it/event/a0439/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The molecular mechanisms of vision: insights in the activation pat
hway of Rhodopsin from classical and mixed quantum-classical MD studies
DTSTART;VALUE=DATE-TIME:20040217T123000Z
DTEND;VALUE=DATE-TIME:20040217T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0444@ictp.it
DESCRIPTION://indico.ictp.it/event/a0444/
LOCATION:ICTP MB-2-239
URL://indico.ictp.it/event/a0444/
END:VEVENT
BEGIN:VEVENT
SUMMARY:2D massless boson\, quantum sine-Gordon model and bosonization: E
lementary introduction. Part II
DTSTART;VALUE=DATE-TIME:20040219T100000Z
DTEND;VALUE=DATE-TIME:20040219T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0446@ictp.it
DESCRIPTION:ABSTRACT:\nThese lectures are complementary to the introductio
n to Conformal\nField Theory given recently by Marina Huerta. Their goal i
s to show \nhow main ideas and mathematical structures of the formal CFT a
pproach\nshow up in a simple and well-known example -- the 2D Gaussian mo
del\n(free massless boson). We will also consider a typical deformation of
\nthis theory\, the 2D sine-Gordon model\, that displays a topological \n
(Berezinskii-Kosterlitz-Thouless) transition. Questions related to \nfermi
on-boson democracy will be finally discussed.\n\n//indico.ictp.it/event/a0
446/
LOCATION:ICTP MB-2-239
URL://indico.ictp.it/event/a0446/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Microscopic Mechanism of antibiotics Translocation through a porin
DTSTART;VALUE=DATE-TIME:20040224T123000Z
DTEND;VALUE=DATE-TIME:20040224T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0449@ictp.it
DESCRIPTION://indico.ictp.it/event/a0449/
LOCATION:ICTP MB-2-239
URL://indico.ictp.it/event/a0449/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wigner delay time: beyond the Random Matrix Theory
DTSTART;VALUE=DATE-TIME:20040226T100000Z
DTEND;VALUE=DATE-TIME:20040226T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0456@ictp.it
DESCRIPTION:ABSTRACT:\nThe time duration of a scattering process in quantu
m mechanics can be\ncharacterized by the so called Wigner delay time. Sta
tistical approach\nto the scattering problems in mesoscopic physics is usu
ally based on\nthe random matrix theory (RMT). The application of the RMT
is limited\nhowever to the situations where there are no non-trivial ener
gy or length\nscales in the system. In this talk the opposite situation is
\nconsidered. Namely\, the statistical properties of the Wigner delay time
s\nare investigated for different models of disordered and chaotic systems
\nexhibiting diffusion or localization.Wigner delay time: beyond the Rando
m Matrix Theory\n\n//indico.ictp.it/event/a0456/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0456/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Effects of system size and time scale in classical molecular dynam
ics \nsimulations of Water
DTSTART;VALUE=DATE-TIME:20040302T123000Z
DTEND;VALUE=DATE-TIME:20040302T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0460@ictp.it
DESCRIPTION://indico.ictp.it/event/a0460/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0460/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Flow-induced voltage along single-walled carbon nanotubes
DTSTART;VALUE=DATE-TIME:20040303T150000Z
DTEND;VALUE=DATE-TIME:20040303T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0459@ictp.it
DESCRIPTION://indico.ictp.it/event/a0459/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0459/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Electrospray-ionization mass spectrometry for protein conformation
al studies
DTSTART;VALUE=DATE-TIME:20040309T123000Z
DTEND;VALUE=DATE-TIME:20040309T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0467@ictp.it
DESCRIPTION://indico.ictp.it/event/a0467/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0467/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tails of the Density of States in a Random Magnetic Field
DTSTART;VALUE=DATE-TIME:20040311T100000Z
DTEND;VALUE=DATE-TIME:20040311T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0468@ictp.it
DESCRIPTION://indico.ictp.it/event/a0468/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0468/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Drug DNA interactions: A QM/MM study
DTSTART;VALUE=DATE-TIME:20040316T123000Z
DTEND;VALUE=DATE-TIME:20040316T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0472@ictp.it
DESCRIPTION:The most promising anticancer drugs nowadays target DNA. There
fore\, a\nprofoundunderstanding of drug-DNA interactions is important in d
rug\ndesign. In this regard\, we have studied two anticancer drugs\, namel
y\ncisplatin and duocarmycin. We used mixed quantum/classical molecular\nd
ynamics simulations in a DFT/plane waves scheme in order to study the\nstr
uctural changes of DNA upon cisplatin binding and the chemical\nreactivity
in water. To validate the results\, comparison between different\nexchang
e and correlation functionals is made.\n\n//indico.ictp.it/event/a0472/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0472/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Smart structures
DTSTART;VALUE=DATE-TIME:20040317T150000Z
DTEND;VALUE=DATE-TIME:20040317T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0471@ictp.it
DESCRIPTION:Abstract: Smart or adaptronic structures are structures with a
n ability to respond in a pre-defined useful and efficient manner to chang
ing environmental conditions\, including any changes in their own conditio
n. Since they are designed and used by human beings\, the overall design
philosophy should encompass the role of the human user also. Another view
point is that they are nothing but a synonym for good engineering. They sh
ould possess characteristics close to\, and\, if possible\, exceeding thos
e found in bio-materials. Adaptability is their main feature. In the so-c
alled passively smart materials\, this comes about as a standby property.
But in actively smart materials or structures there has to be a field-tuna
bility of properties. This\, in turn\, requires nonlinear response. The v
icinity of a ferroic phase transition at the temperature of application pr
ovides the nonlinearity feature. But there are also several other ways of
achieving nonlinear response. Use of soft matter is one such way. Exploita
tion of mesoscopic structure is another. Mimicking biological structures
also entails the incorporation of a “brain” or control centre. Advanc
es in artificial intelligence and neural networks continue to provide the
impetus to the field of smart structures. An overview of the subject will
be given.\n\n//indico.ictp.it/event/a0471/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0471/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SYMMETRIES AND BROKEN SYMMETRIES IN CONDENSED-MATTER PHYSICS
DTSTART;VALUE=DATE-TIME:20040318T100000Z
DTEND;VALUE=DATE-TIME:20040318T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0473@ictp.it
DESCRIPTION:Symmetry and invariance principles have played a vital role in
the \ndevelopment of physics. And just about as ubiquitous as symmetry is
the \nspontaneous breaking of symmetry. In particular\, broken symmetry i
s the \nbasic underlying concept of condensed-matter physics. Crystal grow
th and \nother phase transitions are phenomena involving spontaneous break
ing of \nsymmetry. Generalised rigidity\, as also topological defects like
\ndislocations\, are some of the consequences of the breaking of symmetry
\ninvolved in the formation of a crystal from the highly symmetric fluid
\nphase. The Curie principle\, or rather its generalisation called the \nC
urie-Shubnikov principle\, is the basic symmetry principle of physics. Of
\nparticular interest is the application of this principle to composite \n
objects made up of equal parts (crystals are examples of such composite \n
objects because they are made up of equal parts called unit cells). For \n
such objects the possibility of the manifestation of a new type of \nsymme
try called latent symmetry has been pointed out recently by the \nspeaker
in his book on ferroic materials. Latent symmetry is that \nunexpected ext
ra symmetry which can arise sometimes when two or more \nidentical objects
combine to form a composite in a specific way. The \nnotion of partial sy
mmetry is familiar in crystallography: it is a local \nsymmetry\, rather t
han a global symmetry. Subunits of the object may be \nrelated by a partia
l symmetry\, but the object as a whole does not have \nthat symmetry. By c
ontrast\, latent symmetry is that partial symmetry of a \nsubunit of the b
asic components of a composite made up of equal parts \nwhich is also a gl
obal symmetry of the composite.\n\n//indico.ictp.it/event/a0473/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0473/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Segregation Mechanisms in a Model of an Experimental Binary Granul
ar Mixture
DTSTART;VALUE=DATE-TIME:20040325T100000Z
DTEND;VALUE=DATE-TIME:20040325T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0474@ictp.it
DESCRIPTION:Recent experimental studies of a vibrated granular bed consist
ing of two \nparticle types have shown a transition from a mixed to a segr
egated state \nas the filling fraction is varied. A model of the system i
s introduced \nand investigated numerically. Many of the experimentally o
bserved \nfeatures are reproduced and it is shown that the mixed state to
segregated \nstate transition is a robust phenomenon. The model is used t
o investigate \nand elucidate the segregation mechanism(s) present in the
experiment.\n\n//indico.ictp.it/event/a0474/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0474/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Classical-to-quantum crossover and weak localization in the kicked
quantum rotor
DTSTART;VALUE=DATE-TIME:20040401T100000Z
DTEND;VALUE=DATE-TIME:20040401T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0475@ictp.it
DESCRIPTION:The kicked quantum rotor (a particle freely moving on a circle
\nsubject to periodic delta-kicks) has been studied for decades\nand is on
e of the most popular models of quantum chaos. The\ndynamics of the classi
cal version of the model corresponds\nto the diffusive random walk in the
angular momentum space\nand constant energy absorption. The quantum dynami
cs\nexhibits a phenomenon of the dynamic localization\n(suppression of the
classical diffusion by destructive quantum\ninterference)\, as was discov
ered numerically by Casati et al. in\n1979\, and was believed to be proven
analytically in 1996 by\nAltland and Zirnbauer. I would like to discuss a
very recent\npreprint by Tian\, Kamenev and Larkin (cond-mat/0403482) whi
ch\nreexamines the question of quantum corrections to the diffusion\,\nand
brings to light certain effects apparently missed by the\napproach of Alt
land and Zirnbauer\n\n//indico.ictp.it/event/a0475/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0475/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rumor-like information dissemination in complex computer networks
DTSTART;VALUE=DATE-TIME:20040407T163000Z
DTEND;VALUE=DATE-TIME:20040407T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0483@ictp.it
DESCRIPTION:Abstract: An interesting dynamic process taking place in netwo
rks is the spontaneous spreading of information via rumor-like mechanisms.
In addition to its relevance to social sciences\, such mechanisms also f
orm the basis of an important class of data dissemination protocols in com
puter and communication networks. These protocols\, generally known as ep
idemic-style or gossip protocols\, have recently gained prominence as a ro
bust and scalable methodology for group communications in large distribute
d systems.\n In this talk I will describe the results of our Monte Carlo s
imulation studies of the impact of network architecture on the dynamics of
gossip protocols in computer networks with scale-free and random graph co
nnection topologies. \n Our studies provide new insights in the complex (
and rather unexpected ) interplay between the gossip process and the under
lying network topology. An analytical model of gossip dynamics in these n
etworks will be presented.\n\n//indico.ictp.it/event/a0483/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0483/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Probability of correct detection and size of the structured input
DTSTART;VALUE=DATE-TIME:20040415T160000Z
DTEND;VALUE=DATE-TIME:20040415T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0489@ictp.it
DESCRIPTION:keywords: Hidden Markov Model\, window size / receptive field\
, bayesian statistics\, information theory\n\nAbstract:\n\nConsider an inp
ut which has the structure of a Hidden Markov Model (HMM).\nThe values of
each of the hidden variables probabilistically depends only on\nthe values
of the neighboring ones\, and these are accessible only through\nnoisy ch
annels.\nIn the case of a finite HMM\, using belief propagations algorithm
s\, we\ncalculated analytically in simple cases the probability of correct
\ndetection of a given hidden variable as a function of the size of the HM
M.\nUsing information theory\, one thus defines a window size / receptive
field\nof the HMM\, which corresponds to the set of observations which are
\nrelevant to the detection of the given hidden variable.\n\n//indico.ictp
.it/event/a0489/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0489/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Can strong correlation enhance superconductivity ?
DTSTART;VALUE=DATE-TIME:20040415T100000Z
DTEND;VALUE=DATE-TIME:20040415T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0490@ictp.it
DESCRIPTION:In the seminar I will present recent results concerning the in
terplay of\nstrong correlations and superconductivity. In particular\nI wi
ll show that there exist pairing channels orthogonal to strong\ncorrelatio
n\, which are actually enhanced\, even enormously\, in the \nproximity of
a Mott metal-insulator transition. Since the results have \nbeen obtained
by the Dynamical Mean Field Theory (DMFT)\, I will first \nbriefly outline
this technique. This will force me to discuss Anderson \nimpurity models
which naturally arise within DMFT. I will try to argue \nthat these Anders
on impurity models are not just a mere trick to solve \nDMFT\, but unveil
a kind of local criticality which arises in many \nstrongly correlated met
als near a Mott transition.\nI will discuss how this criticality influence
s the onset of bulk \ncoherence\, with particular emphasis on models for s
trongly correlated \nsuperconductors.\n\n//indico.ictp.it/event/a0490/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0490/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Can strong correlation enhance superconductivity ? Part II
DTSTART;VALUE=DATE-TIME:20040420T100000Z
DTEND;VALUE=DATE-TIME:20040420T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0495@ictp.it
DESCRIPTION:In the seminar I will present recent results concerning the in
terplay of\nstrong correlations and superconductivity. In particular\nI wi
ll show that there exist pairing channels orthogonal to strong\ncorrelatio
n\, which are actually enhanced\, even enormously\, in the \nproximity of
a Mott metal-insulator transition. Since the results have \nbeen obtained
by the Dynamical Mean Field Theory (DMFT)\, I will first \nbriefly outline
this technique. This will force me to discuss Anderson \nimpurity models
which naturally arise within DMFT. I will try to argue \nthat these Anders
on impurity models are not just a mere trick to solve \nDMFT\, but unveil
a kind of local criticality which arises in many \nstrongly correlated met
als near a Mott transition.\nI will discuss how this criticality influence
s the onset of bulk \ncoherence\, with particular emphasis on models for s
trongly correlated \nsuperconductors.\n\n//indico.ictp.it/event/a0495/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0495/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Elasticity of biopolymers: A coarse grained approach
DTSTART;VALUE=DATE-TIME:20040421T153000Z
DTEND;VALUE=DATE-TIME:20040421T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0496@ictp.it
DESCRIPTION://indico.ictp.it/event/a0496/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0496/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Theory of Driven Chaotic Systems\, Random Matrix Theory and the Se
miclassical limit
DTSTART;VALUE=DATE-TIME:20040422T100000Z
DTEND;VALUE=DATE-TIME:20040422T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0499@ictp.it
DESCRIPTION:Quantized chaotic systems are generically characterized by two
energy \nscales: the mean level spacing and the bandwidth. \nThis implies
that with respect to driving such systems have an adiabatic\, \na perturb
ative and a non-perturbative regimes. A \\"strong\\" quantal \nnon-perturb
ative response effect is found for systems that are described \nby random
matrix theory models.\nIs there a similar effect for quantized \\"chaotic\
\" systems ? \nTheoretical arguments cannot exclude the existence of a \\"
weak\\" \nnon-perturbative response effect\, but detailed numerical invest
igations \nresults in an unexpected degree of semiclassical correspondence
.\n\n//indico.ictp.it/event/a0499/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0499/
END:VEVENT
BEGIN:VEVENT
SUMMARY:What determines the menu of the native-state folds of proteins
DTSTART;VALUE=DATE-TIME:20040428T103000Z
DTEND;VALUE=DATE-TIME:20040428T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a04101@ictp.it
DESCRIPTION:Abstract: We present a simple physical model which demonstrate
s that the native state folds of proteins can emerge on the basis of consi
derations of geometry and symmetry. We show that the inherent anisotropy
of a chain molecule\, the geometrical and energetic constraints placed by
the hydrogen bonds and sterics\, and hydrophobicity are sufficient to yiel
d a free energy landscape with broad minima even for a homopolymer. These
minima correspond to marginally compact structures comprising the menu of
folds that proteins choose from to house their native-states in. Our res
ults provide a general framework for understanding the common characterist
ics of globular proteins.\n\n//indico.ictp.it/event/a04101/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a04101/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A Model of Wavefunction Collapse for a Unified Micro- and Macro-Dy
namics
DTSTART;VALUE=DATE-TIME:20040429T100000Z
DTEND;VALUE=DATE-TIME:20040429T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a04105@ictp.it
DESCRIPTION:Collapse models aim at describing\, whithin one single dynamic
al equation\,\nboth the quantum properties of microscopic systems and the
classical\nproperties of macroscopic objects. \n\nWe discuss the properti
es of a stochastic differential equation describing\nthe evolution of a fr
ee particle subject to space-localizations.\nIn particular\, we will see t
hat: \n\na) At the microscopic level the stochastic terms affect in a negl
igible\nway the quantum properties of the system: accordingly\, the model
recovers\nall know predictions of Quantum Mechanics. \n\nb) At the macrosc
opic level\, the wavefunction of the center of mass of a\nmacro-object is
very well localized in space and it moves obeying the\nclassical laws of m
otion.\n\n//indico.ictp.it/event/a04105/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a04105/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kondo resonance revisited
DTSTART;VALUE=DATE-TIME:20040510T130000Z
DTEND;VALUE=DATE-TIME:20040510T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a04108@ictp.it
DESCRIPTION:Abstract: After a brief introduction of the Kondo resonance st
udy on quantum dots and using STM on metallic surfaces\, two pieces of wor
k will be described: \n1) Fano resonance in Anderson impurity systems. It
is shown that the broadening of the impurity level leads to an additional
and important contribution to the Fano resonance around the Fermi energy\
, especially in the mixed valence regime. This contribution comes from th
e interference of the Kondo resonance and the broadened impurity level. T
he theory can quantitatively explain the STM data not only for systems lik
e Co on Au/Ag/Cu surfaces\, but also for Ti on Au/Ag surfaces. (Ref. cond
-mat/0311533). \n2) Swapping entangled Kondo resonances in parallel-couple
d double quantum dots. It is shown that in the Kondo regime with degenera
te dot levels\, the bonding and antibonding states of the Kondo resonances
can be swapped by changing the interdot exchange integral and/or the asym
metric dot-lead coupling ratio. In principle\, this process can be used t
o realize an XOR gate for the quantum computation. (Ref. cond-mat/0403629
).\n\n//indico.ictp.it/event/a04108/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a04108/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fusion Hierarchies of Critical A-D-E Lattice Models
DTSTART;VALUE=DATE-TIME:20040513T100000Z
DTEND;VALUE=DATE-TIME:20040513T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a04115@ictp.it
DESCRIPTION:In 1987\, Pasquier constructed the critical A-D-E lattice mode
ls whose \npartition functions are found to be identical to the modular in
variant \npartition functions of unitary minimal models in conformal field
theory. \nIn this talk\, I will introduce the A-D-E models and show how t
o construct \nnew models from the existing ones by a process called fusion
. The fusion \nprocedure is used to construct integrable boundary conditio
ns and to \nderive the functional equations which can be solved to give th
e spectra of the \ntransfer matrices.\n\n//indico.ictp.it/event/a04115/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a04115/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Exact solution of a linear molecular motor model driven by two-ste
p fluctuations and subject to protein friction
DTSTART;VALUE=DATE-TIME:20040519T150000Z
DTEND;VALUE=DATE-TIME:20040519T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a04116@ictp.it
DESCRIPTION:Abstract: We investigate by analytical means the stochastic eq
uations of motion of a linear molecular motor model based on the concept o
f protein friction. Solving the coupled Langevin equations originally pro
posed by Mogilner et al.\, and averaging over both the two-step internal c
onformational fluctuations and the thermal noise\, we present explicit\, a
nalytical expressions for the average motion and the velocity-force relati
onship.\n\n//indico.ictp.it/event/a04116/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a04116/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mechanical Properties and Enzymatic Function of Aspartic Proteases
DTSTART;VALUE=DATE-TIME:20040520T123000Z
DTEND;VALUE=DATE-TIME:20040520T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a04121@ictp.it
DESCRIPTION:Abstract: The biological function of the homodimeric retropeps
in HIV-1 Aspartic protease has recently been related to the conformational
flexibility of its structural scaffold. Here we address the fundamental i
ssue on whether such mechanism is present also in the other known fold of
aspartic proteases\, that is the asymmetric monomeric fold typical of the
eukariotic isoenzymes (pepsins). We investigate the mechanisms governing t
he enzymatic activity of a typical member of the pepsin family\, human $\\
beta$-secretase\, through classical MD and hybrid Car-Parrinello MD simula
tions. As for the viral isoenzyme\, the reaction free energy is found to b
e strongly modulated by a set of large-scale conformational fluctuations o
f the protein. By using a suitable coarse-grained scheme and multiple sequ
ence alignment techniques we learn that the mechanical response of all mem
bers of the pepsin family is analogous to the $\\beta$-secretase one. In p
articular\, we find that the conserved residues identify three regions of
the protein\, located around the cleavage-site cavity\, in the four $\\bet
a$-sheets cross-linking the two lobes\, and in a solvent-exposede region b
elow the long $\\beta$-hairpin in the N-terminal lobe. Residuese in these
sets play specific roles in the mechanical properties of the enzyme and ye
t are very little mobile. The ubiquity of these features in all analyzed s
tructures suggest that aspartic proteases have been evolutionary selected
to possess similar functional motions which\, in turn\, preserve the enzym
atic activity mechanisms despite the observed fold variations.\n\n//indico
.ictp.it/event/a04121/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a04121/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Transport through interacting quantum wires
DTSTART;VALUE=DATE-TIME:20040520T100000Z
DTEND;VALUE=DATE-TIME:20040520T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a04123@ictp.it
DESCRIPTION:The interplay of electron correlations and impurities in one-d
imensional \nelectron systems leads to striking effects in the low energy
physics. The \nconductance in addition depends strongly on the properties
of the contacts \n(``adiabatic'' versus ``abrupt'').\nResults for the cond
uctance using a functional renormalization group (fRG)\napproach which is
perturbative in the two-body interaction\,\nbut non-perturbative in the im
purity strength are presented. The comparison \nwith exact numerical resul
ts for small chain length shows that the truncated \nfRG is surprisingly a
ccurate even for moderate interaction strength \n(cond-mat/0304517).\nAfte
r presenting fRG results for the scaling function in the case of a \nsingl
e impurity the resonant tunneling through a double barrier is \ndiscusse
d. Calculations of the peak conductance G_p(T) as a function of \ntemperat
ure T over several decades show parameter regimes with distinctive \npower
law behaviour. For intermediate dot parameters and T of the order \nof th
e level spacing of the dot\, G_p(T) is shown to decrease for \ndecreasing
T in a non-universal way. No regime of ``correlated sequential \ntunnelin
g'' is found (cond-mat/0304655).\nAbrupt contacts and more complicated geo
metries\, like ``Y-junctions'' are \ndiscussed shortly.\n\n//indico.ictp.i
t/event/a04123/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a04123/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pressure-induced amorphization\, martensitic transformations and t
he memory glass effect
DTSTART;VALUE=DATE-TIME:20040521T123000Z
DTEND;VALUE=DATE-TIME:20040521T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a04124@ictp.it
DESCRIPTION:A large class of materials are known to transform from a cryst
alline to an \namorphous structure under pressure changes at constant temp
erature. Among \nothers\, typical materials are water (H2O)\, quartz (SiO2
) and berlinite \n(AlPO4). \nOne of the striking (though rather controver
sial) properties observed in \nsome pressure-induced amorphous materials i
s the so-called memory glass \neffect: when the amorphous sample is decomp
ressed\, the initial crystalline \nstructure is recovered\, conserving the
original crystal orientation.\n\nHere\, a model of interacting particles
in two dimensions is studied in \norder to address some issues related to
pressure induced amorphization and \nthe memory glass effect. Two limit sc
enarios are presented according to the \nnature of the mechanical instabil
ities underlying the transformation: a direct\ncrystal-to-amorphous transf
ormation and a martensitic transformation. In \nthe last case the product
phase can be a poly-crystal with a very small \ngrain size and the materia
l can be easily taken as an amorphous material. \nThe memory of this \\"am
orphous\\" structure is a natural consequence of the \nunderlying martensi
tic transformation.\n\n//indico.ictp.it/event/a04124/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a04124/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Constrained molecular dynamics and variational principles in quant
um chemistry: efficient exploration of conical intersection seams.
DTSTART;VALUE=DATE-TIME:20040527T123000Z
DTEND;VALUE=DATE-TIME:20040527T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a04132@ictp.it
DESCRIPTION:Conical intersections (CI) are regions of the potential energy
landscape\nof a chemical system where two or more energy surfaces cross a
nd the\nquantum levels are degenerate.\nThey have an interesting topologic
al structure\, and their existence is\nsignalled by particular geometric p
roperties (the concept of \\"Berry phase\\"\nwas introduced in this framew
ork).\nIndeed\, the importance of CIs has grown in the last years in the f
ield of\nphotochemistry\, since they can represent a very fast reaction ch
annel for the decay of a\nphotochemically excited system.\nAn efficient ex
ploration of these gapless regions can help both in\ninterpreting the expe
rimental data and in suggesting new reaction\nmechanisms. To this end\, we
have developed a strategy based\nupon the methods of constrained molecula
r dynamics and the variational\nprinciples of classical mechanics. This st
rategy\, coupled with high\naccuracy quantum chemistry schemes\, will be d
iscussed in this seminar\,\ntogether with possible applications to realist
ic systems.\n\n//indico.ictp.it/event/a04132/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a04132/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantum Monte Carlo based on two-body density functional theory fo
r fermionic many-body systems: application to $^3$He
DTSTART;VALUE=DATE-TIME:20040622T123000Z
DTEND;VALUE=DATE-TIME:20040622T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a04167@ictp.it
DESCRIPTION:The quantum many-body problem for interacting fermions is not
without its challenges. Computational methods\, [Hartree-Fock (HF)\, dens
ity-functional theory (DFT)\, quantum Monte Carlo (QMC)] methods have aide
d greatly in our understanding of systems containing interacting fermions.
In this study we explore the possibility of constructing a QMC algorithm
based on using the two-body density as the fundamental variable. The fac
t that the two-body density can be used as a fundamental variable (that is
that the energy can be written as a functional of the two-body density\,
and that minimizing the energy as a functional of the two-body density lea
ds to the ground state energy) can be demonstrated via a simple extension
of the proofs for DFT performed originally by Hohenberg and Kohn and later
extended to $N$-representable densities by Levy. For the construction of
a fermionic QMC algorithm we invoke an auxiliary interacting bosonic syst
em which is required to have the same two-body density as the interacting
fermionic system to be investigated (recall that.standard DFT was made int
o an applicable method via invoking an auxiliary non-interacting system).
Such an ansatz leads to an additive correction term in the expression for
the ground state energy. We approximate the correction term using Jastro
w and Jastrow-Slater type wavefunctions. Since our approximate correction
term can be written as an additive two-body and three-body potential\, th
e ground state energy can be evaluated by the standard QMC algorithms for
systems of interacting bosons. We perform calculations on $^3$He\, and de
monstrate that quantitative results can be obtained from our method.\nIn p
articular our energies show good agreement with other calculations where e
quivalent levels of approximation were used (fixed-node quantum Monte Carl
o without backflow and without three-body correlation). Other properties t
hat we have calculated (potential energy\, static structure factor\, radia
l distribution function) are also in good agreement with experiment\, and
previous calculations.\n\nRelated Articles:\n\nP. Hohenberg and W. Kohn\,
Phys. Rev. 136B\, 864 (1964).\n\nW. Kohn and L.~J. Sham\, Phys. Rev. 140\,
A1133 (1965).\n\nM. Levy\, Proc. Nat. Acad. Sci. USA 76\, 6062 (1979).\n\
nS. Moroni\, S. Fantoni\, and G. Senatore\, Phys. Rev. B 52\, 13547 (1995)
.\n\nJ. Casulleras and J. Boronat\, Phys. Rev. Lett. 84\, 3121 (2000).\n\n
//indico.ictp.it/event/a04167/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a04167/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Scaling and universality in polymer solutions from relativistic se
lf-diffusion concepts.
DTSTART;VALUE=DATE-TIME:20040624T151500Z
DTEND;VALUE=DATE-TIME:20040624T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a04170@ictp.it
DESCRIPTION://indico.ictp.it/event/a04170/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a04170/
END:VEVENT
BEGIN:VEVENT
SUMMARY:FIRST PRINCIPLES CALCULATIONS OF QUANTUM TRANSPORT IN NANOSTRUCTUR
ES
DTSTART;VALUE=DATE-TIME:20040706T123000Z
DTEND;VALUE=DATE-TIME:20040706T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a04175@ictp.it
DESCRIPTION:Abstract:\nDetermining the quantum ballistic conductance of a
nanosystem has\nbecome of primary interest in recent years for the promise
of novel\ntechnological applications for nanoscale quantum electronic\nde
vices. In particular\, on the theoretical side\, a fully first\nprinciple
theory of electronic transport is highly desirable. In this\ntalk I will d
iscuss recent advances in the development of efficient\ntechniques to comp
ute quantum conductance from first principles and\nshow examples of protot
ypical applications\, ranging from atomic chains\nto carbon nanotubes and
nanotube assemblies.\n\n//indico.ictp.it/event/a04175/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a04175/
END:VEVENT
BEGIN:VEVENT
SUMMARY:INTRALAYER DIFFUSION PROCESSES RELEVANT TO THE GROWTH OF FCC(110)
METAL SURFACES
DTSTART;VALUE=DATE-TIME:20040728T090000Z
DTEND;VALUE=DATE-TIME:20040728T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a04251@ictp.it
DESCRIPTION:Abstract: We use molecular dynamics simulation to produce a m
ap of the\nadatom migration barriers on fcc(110) metal surfaces. The metal
s have been\nmodeled by many-body potentials within the second moment appr
oximation to\nthe tight-binding model. The estimated barriers are found to
be influenced\nby the proximity of steps and terrace size. For each metal
\, the onset\ntemperatures of some important diffusion processes are estim
ated through a\n1-d exactly solvable growth model constructed to describe
the growth along\nthe [001] and the [1$\\\\overline{1}$0] directions separ
ately.\n\n//indico.ictp.it/event/a04251/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a04251/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The onset of chaotic symbolic synchronization between population i
nversions in an array of weakly-coupled Bose-Einstein condensates
DTSTART;VALUE=DATE-TIME:20040802T163000Z
DTEND;VALUE=DATE-TIME:20040802T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a04296@ictp.it
DESCRIPTION:We investigate the onset of chaotic dynamics of the one-dimens
ional discrete nonlinear Schrödinger equation (DNLSE) with periodic bound
ary conditions in the presence of a single on-site defect. This model desc
ribes a ring of weakly-stochasticity in three different scenarios. We make
use of a suitable Poincaré surface of section and continuation methods.
The global stochasticity is characterized by chaotic symbolic synchronizat
ion between the population inversions of certain pairs of condensates. We
were able to follow the motion along the stochastic layers of different re
sonances in the chaotic self-trapping regime. Moreover\, the time series o
f the Poincaré cycles suggests that in the global stochasticity regime th
e dynamics is\, to some extent\, Markovian\, in spite of the fact that the
condensates are phase locked with almost the same phase. This phase locki
ng induces a peculiar local interference in the matter waves of the conden
sates.\n\n//indico.ictp.it/event/a04296/
LOCATION:ICTP MB-Terrace Level-D
URL://indico.ictp.it/event/a04296/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Towards a new information theory
DTSTART;VALUE=DATE-TIME:20040805T090000Z
DTEND;VALUE=DATE-TIME:20040805T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a04305@ictp.it
DESCRIPTION://indico.ictp.it/event/a04305/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a04305/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics:\n"Efficiency of a Monte-C
arlo algorithm for linear and branched polymers"
DTSTART;VALUE=DATE-TIME:20040914T150000Z
DTEND;VALUE=DATE-TIME:20040914T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a04325@ictp.it
DESCRIPTION:In this talk\, I will discuss the efficiency of Incomplete-Enu
meration(IE) Monte-Carlo algorithm for linear and branched polymers. IE i
s a genetic type MC algorithm which randomly generates a small number of c
onfigurations in each run. We find that there is a qualitative difference
in the efficiency of the algorithm for the two kinds of polymers. For li
near polymers the time to generate an independent sample of n monomers for
large n increases as a polynomial in n but for branched polymers it incre
ases as a stretched exponential(exp(cn^a)\, 0 J the spin effect reduces the conductance to e^2/h.\n\n//indico.ict
p.it/event/a0533/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0533/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and Strong Electron Correlations - "E
lectron interactions and transport between coupled quantum Hall edges"\n
DTSTART;VALUE=DATE-TIME:20050317T100000Z
DTEND;VALUE=DATE-TIME:20050317T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0534@ictp.it
DESCRIPTION:We examine the effects of electron-electron interactions on tr
ansport between edge states in a multilayer integer quantum Hall system. T
he edge states of such a system\, coupled by interlayer tunneling\, form a
two-dimensional\, chiral metal at the sample surface. We calculate the te
mperature-dependent conductivity and the amplitude of conductance fluctuat
ions in this chiral metal\, treating Coulomb interactions and disorder exa
ctly in the weak-tunneling limit. We find that conductivity increases with
increasing temperature\, as observed in recent experiments\, and we show
that the correlation length characterising conductance fluctuations varies
inversely with temperature.\n\n//indico.ictp.it/event/a0534/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0534/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations - "I
nteracting electrons in artificial nanostructures"
DTSTART;VALUE=DATE-TIME:20050331T100000Z
DTEND;VALUE=DATE-TIME:20050331T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0537@ictp.it
DESCRIPTION:Carbon nanotubes and\, more recently\, semiconducting nanowire
s are attracting considerable interest as building blocks for a wide varie
ty of nanodevices. Many relevant proofs of concept have already been provi
ded such as field effect transistors\, elementary logic circuits\, light e
mitting diodes\, lasers\, and biochemical sensors. At the same time\, the
increasing quality of these nanostructures is opening new possibilities fo
r low-temperature applications and for the study of fundamental quantum ph
enomena.\n\nIn this talk I will present the results of mesoscopic transpor
t experiments with individual III-V nanowires and single-walled carbon nan
otubes. In particular I will report on 1) the observation of a tunable Jos
ephson supercurrent in InAs nanowires contacted by superconducting electro
des\, and 2) the observation of orbital Kondo physics in carbon nanotube q
uantum dots.\n\n//indico.ictp.it/event/a0537/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0537/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/Democritos INFORMAL SEMINAR on Chemical Physics - " Com
puter simulation of nanostructures out of equilibrium:\n From photochemist
ry to molecular electronics "
DTSTART;VALUE=DATE-TIME:20050405T100000Z
DTEND;VALUE=DATE-TIME:20050405T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0538@ictp.it
DESCRIPTION://indico.ictp.it/event/a0538/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0538/
END:VEVENT
BEGIN:VEVENT
SUMMARY:INFORMAL SEMINAR on Disorder and Strong Electron Correlations - "C
oulomb drag in high Landau level"\n
DTSTART;VALUE=DATE-TIME:20050407T100000Z
DTEND;VALUE=DATE-TIME:20050407T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0539@ictp.it
DESCRIPTION:Recent experiments on Coulomb drag in the quantum Hall regime
have yielded a number of surprises. The most striking observations are tha
t the Coulomb drag can become negative in high Landau levels and that its
temperature dependence is non-monotonous. We develop a systematic diagramm
atic theory of Coulomb drag in strong magnetic fields explaining these puz
zling experiments. The theory is applicable both in the diffusive and the
ballistic regimes\; we focus on the experimentally relevant ballistic regi
me (interlayer distance $a$ smaller than the cyclotron radius $R_c$). It i
s shown that the drag at strong magnetic fields is an interplay of two con
tributions arising from different sources of particle-hole asymmetry\, nam
ely the curvature of the zero-field electron dispersion and the particle-h
ole asymmetry associated with Landau quantization. The former contribution
is positive and governs the high-temperature increase in the drag resisti
vity. On the other hand\, the latter one\, which is dominant at low $T$\,
has an oscillatory sign (depending on the difference in filling factors of
the two layers) and gives rise to a sharp peak in the temperature depende
nce at $T$ of the order of the Landau level width.\n\n//indico.ictp.it/eve
nt/a0539/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0539/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/Democritos INFORMAL SEMINAR on Chemical Physics - "Con
ductance of a quantum junction: a new formulation suitable for TDDFT and M
BPT ab-initio calculations"
DTSTART;VALUE=DATE-TIME:20050412T100000Z
DTEND;VALUE=DATE-TIME:20050412T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0542@ictp.it
DESCRIPTION://indico.ictp.it/event/a0542/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0542/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and Strong Electron Correlations - "L
ow-temperature decoherence of qubit coupled to background charges"\n
DTSTART;VALUE=DATE-TIME:20050421T100000Z
DTEND;VALUE=DATE-TIME:20050421T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05101@ictp.it
DESCRIPTION:We have found an exact expression for the decoherence rate of
a qubit coupled to fluctuating background charges. At low temperatures T t
he decoherence rate is linear in T while at high temperatures our expressi
on coincides with a known classical solution which is\, however\, reached
in the strong coupling regime at surprisingly high T. A comparison of expe
rimental data with our predictions would give an unambiguous indication of
whether the experimentally observed decoherence of a Josephson-junction q
ubit is due to background charges.\n\n//indico.ictp.it/event/a05101/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05101/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations - "D
ephasing and localization in disordered Luttinger liquids"\n\n
DTSTART;VALUE=DATE-TIME:20050428T100000Z
DTEND;VALUE=DATE-TIME:20050428T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05125@ictp.it
DESCRIPTION:I will review recent advances in our understanding of transpor
t in mesoscopic strongly correlated electron systems in one dimension. Pro
minent examples of these systems are semiconductor quantum wires\, carbon
nanotubes\, and coupled quantum Hall edges running in opposite directions.
I will focus on the interplay between the effects of disorder and interac
tions\; specifically\, on the effects of Anderson localization in a disord
ered Luttinger liquid.\nIn the presence of disorder\, the conductivity at
finite temperature is nonzero only because of inelastic electron-electron
scattering. I will demonstrate that the notions of weak localization and d
ephasing due to Coulomb interactions are applicable to the strongly correl
ated 1D system. The dephasing rate depends strongly on the spin polarizati
on and for spinless electrons is totally different from the Aharonov-Bohm
dephasing rate. With lowering T\, the system exhibits localization transit
ion in many-body Fock space ("Anderson-Fock glass") and the conductivity v
anishes at a critical temperature proportional to the strength of disorder
.\n\n//indico.ictp.it/event/a05125/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05125/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar\n"The multiscaling of ti
me-dependent structure functions in turbulence"\n
DTSTART;VALUE=DATE-TIME:20050511T150000Z
DTEND;VALUE=DATE-TIME:20050511T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05147@ictp.it
DESCRIPTION:We show that different ways of extracting time scales from tim
e-dependent velocity structure functions lead to different dynamic-multisc
aling exponents in fluid turbulence. These exponents are related to equal
-time multiscaling exponents by different classes of bridge relations whic
h we derive. We check this explicitly by detailed numerical simulations of
the GOY shell model for fluid turbulence. Next we apply these ideas to t
he problem of turbulent advection of a passive scalar. Here\, our principa
l results\, obtained analytically and numerically\, illustrate important
principles that appear\, at first sight\, to be surprising. We find\,
e.g.\, that the dynamic exponents depend via bridge relations only on the
equal-time scaling exponents of the velocity field. Thus\, even though e
qual-time structure functions for the passive-scalar and passive-vector pr
oblems display multiscaling\, they show simple dynamic scaling if the adve
cting velocity is of the Kraichnan type. Dynamic multiscaling is obtained
only if the advecting velocity field is itself intermittent.\n\n//indico.i
ctp.it/event/a05147/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a05147/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/Democritos Information Seminar on Chemical Physics:\n"Z
n-porphyrin/C70 complexes for efficient solar cells: Molecular orientation
s\, electronic properties and charge transfer time"
DTSTART;VALUE=DATE-TIME:20050511T103000Z
DTEND;VALUE=DATE-TIME:20050511T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05150@ictp.it
DESCRIPTION:Molecular dyes composed of electron donors capable of photo-in
duced electron transfer to linked acceptors have been used to mimics the n
atural photosynthetic reaction centers in photochemical devices. Porphyri
ns are among the most employed building blocks as electron donors [1]. Int
riguing is the system formed by metallo-porphyrins directly attached to fu
llerenes\, actually realized in co-crystallites and solution form only [2]
\, for which the typical\nfluorescence decay of the excited porphyrins is
strongly quenched [3]\, i.e. non-radiative decay channels are favored. Ne
xt step toward an efficient solar cell is the deposition of similar metall
o-porphyrin/fullerene systems on substrates\, with the ability to control
and tailor the orientation of both molecules (geometric structure and arra
ngement of the molecules are responsible for the physical properties of th
e system). Here\, we demonstrate that the UHV deposition of porphyrins an
d C70 molecules on clean substrates allows the formation of films having s
elected intermolecular interactions and electronic properties. Using polar
ization-dependent x-ray absorption and photoemission spectroscopy we have
investigated the growth\, molecular orientation and electronic properties
of Zn-Tetraphenyl-porphyrin (ZnTPP)/C70 films deposited on Ag(110)\, Si(11
1) and TiO2(110). The quite strong ZnTPP-fullerene interaction allows the
growth of a single ZnTPP layer on top of a C7 \nmonolayer (and vice versa)
\, as well as it allows the self-assembling of the two molecular species i
n ordered multilayer structures when co-deposited. The interactions with t
he substrate and with C70 modify the ZnTPP electronic states\, indicating
formation of bonds and charge redistribution. Resonant photoemission\, wh
ich probes the delocalization (charge transfer) of an excited electron on
the time scale of the core-hole lifetime [4]\, indicates that the ZnTPP/C7
0 mixed systems delocalize more efficiently the excited electrons as compa
red to pure ZnTPP films. The charge transfer time depends on the empty Ã?
â‚¬* state in which the electron is excited and on the relative molecu
lar orientations\, but in general is below 10 fs and in some cases faster
than 5 fs.\n\n//indico.ictp.it/event/a05150/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05150/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations - "T
ypical properties of "glassy" economies"
DTSTART;VALUE=DATE-TIME:20050513T100000Z
DTEND;VALUE=DATE-TIME:20050513T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05156@ictp.it
DESCRIPTION://indico.ictp.it/event/a05156/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05156/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on disorder and strong electron correlations:\n"F
irst steps of a nucleation theory in disordered systems"
DTSTART;VALUE=DATE-TIME:20050519T100000Z
DTEND;VALUE=DATE-TIME:20050519T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05160@ictp.it
DESCRIPTION:I will describe a field theoretical formalism for studying equ
ilibrium relaxation in glassy systems. I will mainly discuss disordered m
odels with large but finite range of interaction and I will define glassy
"effective potentials" which in mean-field are non-convex\, two minima fun
ction of the overlap. Metastability will be associated with the existence
of space inhomogeneous solution of suitable field equations and study the
simplest of such solutions.\n\n//indico.ictp.it/event/a05160/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05160/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations: "Cr
oss-correlations among zeros of Dirichlet L-functions and parametric RMT"\
n
DTSTART;VALUE=DATE-TIME:20050526T100000Z
DTEND;VALUE=DATE-TIME:20050526T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05169@ictp.it
DESCRIPTION:Cross-correlations between critical zeros of different L-funct
ions exhibit properties analogous to cross-correlations between related ch
aotic spectra. This phenomenon can be analysed in the framework of parame
tric random matrix theory. I will also discuss other structures in analyt
ic number theory which exhibit striking similarities to properties of dyna
mical systems.\n\n//indico.ictp.it/event/a05169/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05169/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Colloquim on Mesoscopic physics: From Brownian motion to quantum d
evices
DTSTART;VALUE=DATE-TIME:20050530T151500Z
DTEND;VALUE=DATE-TIME:20050530T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05173@ictp.it
DESCRIPTION:One of the revolutionary papers that Einstein wrote in 1905 is
devoted to the theory of the Brownian motion - motion of particles that a
re small enough to feel the molecular motion\, and large enough to be obse
rved individually. Einstein proposed statistical analysis of the motion of
each Brownian particle and derived Diffusion equation to perform this ana
lysis. This idea of statistical approach is so crucial for modern mesoscop
ic physics\, that it would be an fare to start the history of the field fr
om the celebrated Einstein's paper. Mesoscopic (sample-specific) effects a
re usually rather weak in classical systems. Quantum interference enhances
them tremendously. Mesoscopic effects become increasingly important with
miniaturization of the devices. As to the nanostructures\, these effects s
imply dominate. We will briefly discuss the history and current status of
the theory of quantum transport and its connection with the general descri
ption of complex quantum integrable and chaotic systems.\n\n//indico.ictp.
it/event/a05173/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a05173/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Disorder and strong electron correlations:\n"C
an a fractional charge tunnel through an insulator?" \n
DTSTART;VALUE=DATE-TIME:20050602T100000Z
DTEND;VALUE=DATE-TIME:20050602T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05181@ictp.it
DESCRIPTION:It is widely believed that the answer to the question in the t
itle is in the negative. The exclusion of such a process - tunneling of a
fractionally charged quasi-particle through a potential barrier (an insul
ator) goes back to a "global constraint": the number of charge carriers on
either side of the barrier must be (nearly) an integer. We address the i
ssue of a QP tunneling in connection with geometries where this constraint
does not apply\, point out to the feasibility of such tunneling and evalu
ate its amplitude.\n\n//indico.ictp.it/event/a05181/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05181/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations - "O
ne-dimensional gapped phases: An attempt to a classification through duali
ty symmetries"\n\n
DTSTART;VALUE=DATE-TIME:20050609T100000Z
DTEND;VALUE=DATE-TIME:20050609T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05263@ictp.it
DESCRIPTION:In this talk\, I am going to discuss on a possible attempt to
a classification of one-dimensional fully-gapped phases. In particular\, w
e will reveal the existence of hidden duality symmetries in the low-energy
limit which relate different ordered phases. The description of the gappe
d phases of the generalized two-leg spin ladder will be described using th
is duality approach.\n\n//indico.ictp.it/event/a05263/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05263/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar: "Structure control of m
etal nano wire via electrochemical potential control"
DTSTART;VALUE=DATE-TIME:20050615T150000Z
DTEND;VALUE=DATE-TIME:20050615T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05268@ictp.it
DESCRIPTION:The electrical conductance through an atomic scale metal nano
constriction is quantized. The conductance quantization has attracted wid
e attention not only for fundamental science but also for technological ap
plication. We have studied the conductance of metal nano constriction in
solution.\nMetal nano constrictions were prepared by pressing a scanning t
unneling microscopy (STM) tip into a substrate and then pulling out of con
tact in an electrochemical cell. For Au nano constriction\, the Au STM ti
p and Au(111) substrate is used. For the preparation of nano constriction
s using other metals (Ni\, Pd\, Cu\, Ag)\, electrochemical metal depositio
n was carried out on to both Au substrate and STM Au tip in solution.\nIn
case of Au nano contact\, a 1 nm long mono atomic wire is fabricated in so
lution at room temperature\, and its stability is controlled by electroche
mical potential. As well as unit value of G0\, additional fractional valu
es also appeared in the conductance histogram\, when the electrochemical p
otential of the system was kept below the hydrogen evolution potential. T
he intensity of the fractional conductance peak increased when the system
was polarized at the negative potential. The result implies that adsorbed
hydrogen contributes to stabilize the certain atomic configuration of mon
o atomic wire. It was proved that the electrochemical potential can contr
ol the stability of the mono atomic wire\, and its structure.\nFor other m
etals\, we also observed change in the conductance quantization behavior d
epending on the electrochemical potential. In case of Pd\, clear conducta
nce quantization appeared at the negative polarization. It is the first o
bservation of the conductance quantization of Pd mono-atomic contact prepa
red at room temperature.\n\n//indico.ictp.it/event/a05268/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a05268/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations: " L
ocalized growth modes\, dynamic textures\, and upper critical dimension fo
r the Kardar-Parisi-Zhang equation in the weak noise limit "\n
DTSTART;VALUE=DATE-TIME:20050616T100000Z
DTEND;VALUE=DATE-TIME:20050616T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05269@ictp.it
DESCRIPTION:A weak noise scheme is applied to the Kardar-Parisi-Zhang equa
tion for a growing interface in all dimensions. It is shown that the solut
ions can be interpreted in terms of a growth morphology of a dynamically e
volving texture of localized growth modes with superimposed diffusive mode
s. Applying Derrick's theorem it is conjectured that the upper critical di
mension is four.\n\n//indico.ictp.it/event/a05269/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05269/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/Democritos Informal Seminar on Chemical Physics:\n"Phon
ons of carbon nanostructures: A local study with inelastic electron tunnel
ling spectroscopy"\n
DTSTART;VALUE=DATE-TIME:20050621T143000Z
DTEND;VALUE=DATE-TIME:20050621T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05271@ictp.it
DESCRIPTION:The phonon spectrum of highly oriented pyrolitic graphite and
of single wall carbon nanotubes was studied with inelastic electron tunnel
ing spectroscopy using a low temperature scanning tunneling microscope. T
he measured inelastic spectrum of graphite is found to be directly proport
ional to the calculated vibrational density of states. Based on the elect
ronic band structure of graphite we suggest that a phonon-assisted tunneli
ng process influences the amplitude of the observed inelastic spectrum. [1
]. Similarly the phonon spectrum of single wall carbon nanotubes adsorbed
on Au substrates was measured. On the low energy part of the spectrum th
e radial breathing mode (RBM) has been identified and its linear dependenc
e on the inverse of the tube diameter demonstrated. Furthermore\, based o
n the high spacial resolution typical of the scanning tunneling technique\
, the behavior of the radial mode becomes accessible in close proximity to
topological defects\, like intermolecular junctions\, tube endings [2]\,
or crossed junctions of tubes where the tube cage is sensitively deformed.
\n\n[1] L.Vitali et al\, Physical Review B.69.121414R (2004)\n[2] L.V
itali et al\, Physical Review Letters 93.136103.(2004)\n\n//indico.ictp.i
t/event/a05271/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05271/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/Democritos Informal Seminar on Chemical Physics:\n"What
can we learn from the nanoscale mechanical response of biomolecules?"
DTSTART;VALUE=DATE-TIME:20050623T140000Z
DTEND;VALUE=DATE-TIME:20050623T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05273@ictp.it
DESCRIPTION:The applications of scanning probe microscopy (SPM) to surface
science are\, of course\, countless and have brought a real revolution to
the field. Less expected but\, a posteriori\, equally logical is the revo
lution that single molecule experimentation (with both SPM and other probe
s) is bringing to the study of macromolecules of both biological and non-
biological origin. On the other hand\, in this journey towards single mole
cule studies it is actually at present possible to choose the size of the
sample rather freely. Each size ( 1 or 1\,000 or 1\,000\,000 molecules or
even the bulk ) has its own advantages and drawbacks both experimentally
and theoretically. \n After having given a couple of examples ( taken from
the work of others ) of experiments on biomolecules at the single molecul
e level \, I will show evidence from our own laboratory that working at t
he hundreds of molecules level\, presents some unique advantages that make
this type of experiments well worth pursuing. After having introduced the
methods that give us the possibility to isolate a sample on the order of
100 to 1\,000 molecules in the middle of a reference ( larger ) set of sim
ilar molecules\, I will apply the time honored method of differential meas
urements to study the properties of monolayers of molecules of incresing c
omplexity. \n Starting with saturated hydrocarbons and short strands of p
olyethylene glycol ( a molecule of great importance in the field of biocom
patibility ) I will move to the study of small patches of DNA and some ver
y recent results on proteins. The second class of results will be presente
d as an example of why quite a few people are presently convinced\, that t
he field of "NanoBio" is not just a fad but may actually be our ticket to
understand at least some of the complexities of a living cell.\n\n//indico
.ictp.it/event/a05273/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a05273/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics:\n"An analytical probabili
stic approach to the ground state of lattice systems"
DTSTART;VALUE=DATE-TIME:20050629T150000Z
DTEND;VALUE=DATE-TIME:20050629T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05277@ictp.it
DESCRIPTION:We present a new approach to the ground state of a lattice sys
tem whose evolution is governed by an arbitrary finite Hamiltonian matrix
H. We show that the ground state of H can be analytically determined thr
ough the probability distribution of the underlying classical dynamics. So
me possible applications of the present approach will also be discussed.\n
\n//indico.ictp.it/event/a05277/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a05277/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar: "Melting transition in
elemental materials from ab-initio molecular dynamics"
DTSTART;VALUE=DATE-TIME:20050713T150000Z
DTEND;VALUE=DATE-TIME:20050713T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05289@ictp.it
DESCRIPTION:It is currently possible to compute reliably the free energy o
f a material at finite temperature and pressure from the quantum mechanica
l ground state of the electrons within density functional theory. The free
energy is obtained by thermodynamic integration in the context of ab-init
io molecular dynamics. By applying this approach to coexisting liquid and
solid phases\, one can predict a melting line from first-principles micros
copic theory. In this talk I will review the basic computational approach\
, and will discuss how different approximations for the exchange and corre
lation functional affect the predicted phase diagram. Finally I will prese
nt a recent application in which this scheme has been used to determine th
e diamond melting line in an extended range of temperatures and pressures.
This coexistence line is poorly known from experiment\, given the extreme
pressures and temperatures that are required to melt diamond. The implic
ations of the newly predicted carbon phase diagram will be discussed.\n\n/
/indico.ictp.it/event/a05289/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a05289/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/Democritos Informal Seminar on Chemical Physics: "Physi
cal properties of minerals and oxides at high pressures: Structural and el
astic effects of chemical substitutions and electronic transitions"
DTSTART;VALUE=DATE-TIME:20050714T143000Z
DTEND;VALUE=DATE-TIME:20050714T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05290@ictp.it
DESCRIPTION:High-p3 pressure mineral physics investigates the properties o
f candidate components of the Earth deep interior and allows us to compare
mineralogical models with both geochemical and geophysical constraints.
The experimental techniques of mineral physics allow us to investigate the
properties of a wide range of Earth materials. \nIn this talk I will pres
ent selected results of my research regarding (a) the compositional depen
dence of elasticity in olivine and minerals of the upper mantle (b) the ef
fect of the high-spin to low spin transition of Fe on the compressibility
of (Mg\,Fe)O ferropericlase at lower mantle pressures\, (c) a possible mec
hanism for valence change of Fe in hydrous minerals in the subducting lith
ospheric slabs and upper mantle based on vibrational spectroscopy of Fe(OH
)2.\n\n//indico.ictp.it/event/a05290/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05290/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar: "Generalized transition state"
DTSTART;VALUE=DATE-TIME:20050722T100000Z
DTEND;VALUE=DATE-TIME:20050722T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05306@ictp.it
DESCRIPTION:We propose a computational scheme for materials where standard
Local Density Approximation (LDA) fails to produce a satisfactory descrip
tion of excitation energies . The method uses Slater's "transition state"
approximation and Wannier functions basis set. We define a correction to
LDA functional in such a way that its variation produces one-electron ener
gies for Wannier functions equal to the energies obtained in "transition s
tate" constrained LDA calculations. In the result eigenvalues of the prop
osed functional could be interpreted as excitation energies of the system
under consideration. The method was applied to MgO\, Si\, NiO and BaBiO$_
3$ and gave an improved agreement with experimental data of energy gap val
ues comparing with LDA.\n\n//indico.ictp.it/event/a05306/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05306/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations:\n"S
pectral statistics of a quantum interval exchange map" \n
DTSTART;VALUE=DATE-TIME:20050804T100000Z
DTEND;VALUE=DATE-TIME:20050804T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05316@ictp.it
DESCRIPTION:Curious spectral properties of an ensemble of random unitary m
atrices appearing naturally in the quantization of a simple interval-excha
nge map are investigated. It is demonstrated that\, under certain conditi
ons on map parameters\, local spectral statistics of this ensemble tends t
o the semi-Poisson distribution with arbitrary integer or half-integer lev
el repulsion at small distances depending on time-reversal symmetry of the
map.\n\n//indico.ictp.it/event/a05316/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05316/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: 'Two applications of stat
istical physics to machine-learning and information theory'
DTSTART;VALUE=DATE-TIME:20050915T100000Z
DTEND;VALUE=DATE-TIME:20050915T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05335@ictp.it
DESCRIPTION:I will present two short works in which methods from statistic
al mechanics are applied in a machine learning problem of semi-supervised
learning\, and an engineering application of two-dimensional channels.\n\n
//indico.ictp.it/event/a05335/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05335/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on: Disorder and strong electron correlations\n"S
olvable model of a random spin-1/2 XY chain"
DTSTART;VALUE=DATE-TIME:20050929T100000Z
DTEND;VALUE=DATE-TIME:20050929T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05343@ictp.it
DESCRIPTION:In my talk I present exact calculations of thermodynamic quant
ities for the spin-1/2 isotropic XY chain with random Lorentzian intersite
interaction and transverse field that depends linearly on the surrounding
intersite interactions.\n\n//indico.ictp.it/event/a05343/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05343/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations\n"Bo
sonic stimulation and statistical fluctuations: A strangeness of proportio
n"
DTSTART;VALUE=DATE-TIME:20051006T100000Z
DTEND;VALUE=DATE-TIME:20051006T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05345@ictp.it
DESCRIPTION:The kinematics of Bose statistics for the scattering of incomi
ng bosons into a set of non-overlapping\, degenerate single-particle state
s\, is shown to manifest a non-ergodic and symmetry-breaking behaviour sim
ilar to the Polya urn problem\, familiar in diverse situations ranging fro
m population biology to economics. It is a purely statistical consequence
of bosonic stimulation\, which favours scattering into a state with an alr
eady higher occupation number. Possible realization is briefly discussed.
\n\n//indico.ictp.it/event/a05345/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05345/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special informal seminar on Disorder and strong electron correlati
ons:\n"Doped spin liquid: Luttinger sum rule and low temperature order"\n
DTSTART;VALUE=DATE-TIME:20051010T100000Z
DTEND;VALUE=DATE-TIME:20051010T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05348@ictp.it
DESCRIPTION:We analyze a model of two-leg Hubbard ladders weakly coupled b
y interladder tunneling. At half filling a semimetallic state with small F
ermi pockets is induced beyond a threshold tunneling strength. The sign c
hanges in the single electron Green's function relevant for the Luttinger
Sum Rule now take place at surfaces with both zeroes and infinities with i
mportant consequences for the interpretation of ARPES experiments. Residu
al interactions betwen electron and hole-like quasi-particles cause a tran
sition to long range order at low temperatures. The theory can be extende
d to small doping leading to superconducting order.\n\n//indico.ictp.it/ev
ent/a05348/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05348/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/Democritos Informal Seminar on Chemical Physics: "Segre
gation-induced alloy nanocluster thermodynamical properties: FCEM computa
tions with energetics based on surface/subsurface bond strength variations
"\n\n
DTSTART;VALUE=DATE-TIME:20051011T100000Z
DTEND;VALUE=DATE-TIME:20051011T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05351@ictp.it
DESCRIPTION:The free-energy concentration expansion method (FCEM) is an ef
ficient tool for elucidating site-specific compositions in multicomponent
medium size alloy nanoclusters\, that are inaccessible by current experime
ntal techniques (and by some theoretical approaches). FCEM computations\,
in conjunction with energetics based on surface/subsurface bond strength v
ariations obtained by the NRL-TB method\, were accomplished for Rh-Pd-Cu a
nd the corresponding binary Rh-Cu\, Pd-Cu and Rh-Pd nanocluster systems ca
pable of inter-cluster atom exchanging. The cluster sizes range from 55 t
o 923 atoms with perfect cuboctahedral shape. The computed segregated str
uctures exhibit several phenomena such as surface induced order (Pd-Cu) an
d sequential multi-site segregation (Rh-Pd-Cu). The data form the basis fo
r evaluating pertinent "cluster thermodynamic functions"\, such as the con
figurational entropy and heat-capacity. For all systems Schottky-type hea
t capacity anomaly is predicted and attributed to intra-cluster atomic exc
hange (e.g.\, desegregation) excitation processes. For Rh-Cu\, Rh-Pd and
Rh-Pd-Cu the cluster system is expected to separate into "magic-numbe" ord
ered structures\, with transition temperatures estimated from the disappea
rance of convexity in the free-energy vs. composition curves.\n\n//indico.
ictp.it/event/a05351/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05351/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on disorder and strong electron correlations:\n"C
oulomb interaction and nanoscale electronic inhomogeneities" \n
DTSTART;VALUE=DATE-TIME:20051013T100000Z
DTEND;VALUE=DATE-TIME:20051013T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05352@ictp.it
DESCRIPTION:In a number of systems\, there seems to be experimental eviden
ce for electronic inhomogeneities on a length scale of the order of nanome
tres\; examples are manganites\, cuprates\, cobaltates\, etc.. I describe
a lattice model with two different microscopic states at each site\, and
long range coulomb interactions. Extensive numerical work reported here s
hows that the separation into two phases is muted to nanoscale inhomogenei
ties as a consequence of the coulomb interaction. The nature and extent o
f this is discussed as a function of relevant physical parameters\, and ap
plied to manganites and cobaltates.\n------------------------------\nThe a
bove work has been done by T. Gupta\, V. Shenoy\, H.R. Krishnamurthy and T
.V. Ramakrishnan at the Indian Institute of Science\, Bangalore.\n\n//indi
co.ictp.it/event/a05352/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05352/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar on:" Microscopic mechani
sms of friction"
DTSTART;VALUE=DATE-TIME:20051014T100000Z
DTEND;VALUE=DATE-TIME:20051014T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05353@ictp.it
DESCRIPTION:This talk will be devoted to a computer simulation of the micr
oscopic mechanisms of friction. First\, I will give a brief overview of t
he main friction facts and laws. Then\, I will present a molecular dynami
cs technique for a film confined between two substrates in moving contact\
, based on Langevin equations with a coordinate- and velocity-dependent da
mping coefficient. The simulation results show that the microscopic mecha
nism of stick-slip motion depends on the ratio of the strength of interact
ion within the lubricant and the lubricant-substrate interaction. For a
"hard" lubricant\, when the lubricant film remains in a solid state during
sliding\, the stick-slip is due to inertia effects\, while for a "soft"
lubricant\, when the lubricant-substrate interaction is much larger than t
he interaction within the lubricant\, the stick-slip motion is due to the
melting-freezing mechanism. An optimal choice of the interaction within
the lubricant leads to a self-ordering of the lubricant film and results i
n a minimal kinetic friction. Finally\, I will briefly discuss some open
problems of friction\, such as the minimal velocity of the transition fro
m smooth sliding to stick-slip motion\, the role of the slider geometry\,
the role of the shape of lubricant molecules\, and the problem of calcul
ation of the static and kinetic friction coefficients.\n\n//indico.ictp.it
/event/a05353/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05353/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/Democritos Informal Seminar on Chemical Physics:\n"Elec
tromechanical effects in carbon nanotubes"
DTSTART;VALUE=DATE-TIME:20051018T100000Z
DTEND;VALUE=DATE-TIME:20051018T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05349@ictp.it
DESCRIPTION:We perform ab initio calculations of charged graphene and sing
le-wall carbon nanotubes (CNTs)\, obtaining a wealth of electromechanical
behaviours:\n\n(1) Both nanotubes and graphene expand upon electron inject
ion.\n(2) Upon hole injection\, metallic nanotubes and graphene display a
nonmonotonic behaviour. Upon increasing hole densities\, the lattice cons
tant initially contracts\, reaches a minimum\, and then starts to expand.
The hole densities at minimum lattice constants are 0.3 |e|/atom for grap
hene and between 0.1 and 0.3|e|/atom for the metallic nanotubes studied.\n
(3) Semiconducting CNT's with small diameters (d ~ 20 A) display a behavio
ur intermediate between those of metallic and large-gap CNT's.\n(5) The st
rain versus extra charge displays a linear plus power-law behaviour\, with
characteristic exponents for graphene\, metallic\, and semiconducting CNT
's.\n\nAll these features are physically understood within a simple tight-
binding total-energy model.\n\n//indico.ictp.it/event/a05349/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05349/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar:\n" Vacancy-impurity nan
oclusters in solid solutions 3He - 4He" \n
DTSTART;VALUE=DATE-TIME:20051019T150000Z
DTEND;VALUE=DATE-TIME:20051019T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05358@ictp.it
DESCRIPTION:Vacancies and impurities in solid helium are delocalized and c
an be considered as quasiparticles (defectons) that move through the latti
ce as free particles with a complicated dispersion law. Vacancy-impurity
clusters in solid solutions of helium isotopes near the phase separation t
ransition appear due to the quantum nature of vacancies and impurities in
quantum crystals and have no classical analogues. They were predicted by
the author as a part of a series effects which can strongly influence the
kinetics of the phase transitions at very low temperatures. Some ground p
roperties of the clusters are considered and the theoretical estimations a
re compared with the experimental results. Some other effects of defectons
on the crystal lattice structure are analysed.\n\n//indico.ictp.it/event/
a05358/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a05358/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on disorder and strong electron correlations: "Fo
rm factors study of a one parameter family of integrable massless flows"\n
DTSTART;VALUE=DATE-TIME:20051020T100000Z
DTEND;VALUE=DATE-TIME:20051020T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05359@ictp.it
DESCRIPTION:Massless flows from the coset model su(2)_{k+1}* su(2)_k/su(2)
_{2k+1} to the minimal model M_{k+2} are studied from the viewpoint of for
m factors. These flows include in particular the well-known flow from the
Tricritical Ising model to the Ising model. We will first discuss the fo
rm factors of the trace operator\, and provide numerical checks on the val
ue of the central charge. Large discrepancies with respect to the exact r
esults are observed in most cases. \nThen\, we will consider the form fac
tors of an (a priori unknown) operator that renormalises on Phi_{2\,2} in
the IR\, and we will identify numerically the operator in the UV as being
Phi_{2\,2}.\n\n//indico.ictp.it/event/a05359/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05359/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: " Cooperative lengthscale
s in glass-formers: Theoretical motivations and empirical evidence "
DTSTART;VALUE=DATE-TIME:20051021T133000Z
DTEND;VALUE=DATE-TIME:20051021T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05360@ictp.it
DESCRIPTION:After decades of research\, a clear picture of the glass trans
ition phenomenon common to scores of different materials (molecular glasse
s\, polymers\, colloids) is still lacking. Recent theoretical works sugge
st the existence of dynamic criticality and growing dynamic lengthscales a
ssociated to dynamic heterogeneity. We will summarize the theoretical arg
uments for such a length scale and discuss experimentally accessible multi
-point dynamic susceptibilities quantifying the cooperative dynamics. We
will present some recent numerical and experimental results illustrating t
hese ideas.\n\n//indico.ictp.it/event/a05360/
LOCATION:ICTP - Main Building Room D (Terrace Level)
URL://indico.ictp.it/event/a05360/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special Informal Seminar on Disorder and strong electron correlati
ons "Variable range cotunneling and \nconductivity of a granular metal"\n\
n\n\n\n\n
DTSTART;VALUE=DATE-TIME:20051025T100000Z
DTEND;VALUE=DATE-TIME:20051025T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05364@ictp.it
DESCRIPTION:The Efros-Shklovskii law for the conductivity of granular meta
ls is interpreted as a result of a variable range cotunneling process. Th
e cotunneling between distant resonant grains is predominantly elastic at
low T T_c. The corresponding E-S temperature T_ES in the latter case is
slightly (logarithmically) T-dependent. The magnetoresistance in the two c
ases is different: it may be relatively strong and negative at T much belo
w T_c\, while at T>T_c it is suppressed due to inelastic processes which d
estroy the interference.\n\n//indico.ictp.it/event/a05364/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05364/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar: " Exploring crystal pol
ymorphism by metadynamics "
DTSTART;VALUE=DATE-TIME:20051026T150000Z
DTEND;VALUE=DATE-TIME:20051026T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05365@ictp.it
DESCRIPTION:Recently we introduced a new method for the study of structura
l transformations in crystals which represents a conceptual extension of t
he idea of constant-pressure simulation (R. Martonak\, A. Laio and M. Parr
inello\, Phys. Rev. Lett.\, 2003\, 90\, 075503). Instead of the latter\,
we start from the initial crystal structure and perform a search for new
minima of the Gibbs potential\, corresponding to new structures. The expl
oration of the free energy surface is performed in the space of the parame
ters of the simulation cell (as in the Parrinello-Rahman method) by means
of metadynamics (A. Laio and M. Parrinello\, Proc. Natl. Acad. Sci. USA 99
\, 12562 (2002)). We present recent results obtained by applying the meth
od to structure prediction in zeolite\, benzene\, the post-perovskite phas
e of MgSiO3 and silica. These examples demonstrate that even in highly co
mplex polyatomic materials with large kinetic barriers as well as in organ
ic crystals our approach allows a very efficient prediction of the polymor
phs (for review\, see R. Martonak et al.\, Z. fuer Kristallographie\, 220\
, 489 (2005)).\n\n//indico.ictp.it/event/a05365/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a05365/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Disorder and strong electron correlations: "M
icroscopic construction of the \nchiral Luttinger liquid"\n\n\n
DTSTART;VALUE=DATE-TIME:20051027T100000Z
DTEND;VALUE=DATE-TIME:20051027T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05363@ictp.it
DESCRIPTION:In this talk I shall discuss the properties of an effective th
eory of the quantum Hall edge in terms of the low-energy projection of the
complete many-body Hilbert space. An explicit construction of the low-en
ergy projection operator will be given and it will be shown how the proper
ties of local operators are modified by the projection. Possible applicat
ions of the approach to the understanding of the observed non-universality
of scaling of fermion spectral density at the edge will be discussed.\n\n
//indico.ictp.it/event/a05363/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05363/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar: " Magnetic field induce
d rotation of the d-vector in the spin triplet superconductor Sr2Ru04 "
DTSTART;VALUE=DATE-TIME:20051102T150000Z
DTEND;VALUE=DATE-TIME:20051102T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05368@ictp.it
DESCRIPTION:We study the superconducting properties of Sr2Ru04 in presence
of spin-orbit coupling [1-2] and magnetic field along the crystal c-axis
. On the basis of a phenomenological but orbital specific description of
the spin dependent electron-electron attraction and a realistic quantitati
ve account of the electronic structure in the normal state we analyze the
orientation of a spin triplet Cooper pair d-vector by comparing condensati
on free energy for particular solutions. In agreement with recent experim
ents we predict the d-vector rotation by the field and a quantum phase tra
nsition [3].\n\n[1] J.F. Annett\, G. Litak\, B.L. Gyorffy\, K.I. Wysokinsk
i\, 'Interlayer Coupling and P-wave Pairing in Strontium Ruthenate'\, Phys
.Rev. B 66 (20020 134514.\n[2] J.F. Annett\, G. Litak\, B.L. Gyorffy\, K.I
. Wysokinski\, 'Spin -Orbit Coupling and Symmetry of the Order Parameter i
n Strontium Ruthenate'\, Phys.Rev. B (2005) submitted.\n[3] H. Murakawa\,
K. Ishida\, K. Kitagawa\, Z.Q. Mao and Y. Maeno\, 'Measurement of the 101
Ru-Knight Shift of Superconducting Sr2Ru04 in a Parallel Magnetic Field'\,
Phys.Rev. Lett. 93 (2004) 167004.\n\n//indico.ictp.it/event/a05368/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a05368/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Statistical Physics:" Statistical mechanics
of random replicators and matrix games "\n
DTSTART;VALUE=DATE-TIME:20051108T150000Z
DTEND;VALUE=DATE-TIME:20051108T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05376@ictp.it
DESCRIPTION:An important objective of game theory consists in the static s
tudy of Nash equilibria of different games. Popular cases are situations
in which the payoffs take matrix form\, the well-known prisoner's dilemma
or the rock-scissors-paper game are simple examples.\nReplicator equations
on the other hand describe the dynamic evolution of self-reproducing inte
racting species for example in population dynamics and theoretical biology
. These equations correspond to matrix games which are played repeatedly
by players\, who then reproduce according to their success.\nIn this talk
we will discuss some recent statistical mechanics studies of replicator sy
stems with random couplings and give an overview over their basic phenomen
ological behaviour. We will address different ergodic/non-ergodic phase t
ransitions exhibited by such models. Some work in progress on the connect
ion between ergodicity in bi-matrix replicator systems and the number of N
ash equilibria in the corresponding games will be discussed\, as well as t
heir relation to the fixed points of the replicator dynamics.\n\n//indico.
ictp.it/event/a05376/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a05376/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations:\n"S
ubgap states in dirty superconductors and dimensional reduction"
DTSTART;VALUE=DATE-TIME:20051117T100000Z
DTEND;VALUE=DATE-TIME:20051117T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05382@ictp.it
DESCRIPTION:I will discuss the physics of subgap localized quasiparticle s
tates in diffusive superconductors. In particular\, I will show how the d
oping of a diffusive superconductor with magnetic impurities leads to the
emergence of localized subgap quasiparticle states resulting from both flu
ctuations of the concentration of impurity spins (classical fluctuations)\
, and quantum interference effects (mesoscopic fluctuations). The contrib
utions to the subgap DOS associated to the two types of fluctuations are r
elated by a dimensional reduction. Finally\, I will show that these obser
vations are generic: the complementarity between classical and mesoscopic
fluctuations\, as well as the relation between the associated subgap DOS i
n terms of dimensional reduction\, emerges in other problems in the theory
of disordered superconductors\, such as in diffusive SNS junctions\, and
superconductors with inhomogeneous coupling constants.\n\n//indico.ictp.it
/event/a05382/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05382/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Informal Seminar:\n"Weak locali
zation and the distribution function of transmission eigenvalues"
DTSTART;VALUE=DATE-TIME:20051123T150000Z
DTEND;VALUE=DATE-TIME:20051123T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05385@ictp.it
DESCRIPTION:Circuit Theory is a microscopic approach which allows for the
calculation of transport properties (conductance\, noise\, etc) of compoun
d systems which often are encountered in mesoscopic physics\, for instance
a quantum point contact in series to diffusive wire or a normal metal-sup
erconductor junction. Here we present a systematic method to include weak
localization effects in the CT. The same method also allows to treat the
sample to sample fluctuations of transmission distribution. The chain of
tunnel junctions and the quantum point contacts with impurities will be il
lustrated as examples of this technique.\n\n//indico.ictp.it/event/a05385/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a05385/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations\n"Si
ngle-electron tunnelling with strong mechanical feedback"\n
DTSTART;VALUE=DATE-TIME:20051124T100000Z
DTEND;VALUE=DATE-TIME:20051124T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05386@ictp.it
DESCRIPTION:We will first describe nanomechanical properties of suspended
carbon nanotubes. Then we specifically consider weak coupling regime and
investigate effect of mechanical degrees of freedom on transport propertie
s. In certain situations\, strong mechanical feedback occurs\, which lead
s to considerable renormalization of current and current noise.\n\n//indic
o.ictp.it/event/a05386/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05386/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar: "Studies on effects of
Dzyaloshinskii-Moriya interactions" \n
DTSTART;VALUE=DATE-TIME:20051130T150000Z
DTEND;VALUE=DATE-TIME:20051130T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05388@ictp.it
DESCRIPTION:Dzyaloshinskii-Moriya (DM) interaction\, due to its relativist
ic origin\, usually is less important in magnetic systems\, compared with
the Heisenberg term. However\, in some low-dimensional magnetic systems l
ike benzoate the DM interaction substantially modifies the low-energy exci
tation spectrum\, especially in the presence of a magnetic field. The den
sity matrix renormalization group studies confirm some results of the conf
ormal field theory\, but make new predictions on crossover between low-fi
eld and high-field phenomena\, to be checked by experiments. The midgap s
tates in antiferromagnetic Heisenberg chains and ladders in a staggered fi
eld have also been studied\, revealing new features to be confronted with
experiments.\n\n//indico.ictp.it/event/a05388/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a05388/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations:\n"S
pin -1/2 fermions on spin-dependent optical lattices"\n
DTSTART;VALUE=DATE-TIME:20051201T100000Z
DTEND;VALUE=DATE-TIME:20051201T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05391@ictp.it
DESCRIPTION:We study the phase diagram of one-dimensional two-component (i
.e. pseudo-"spin" 1/2) ultracold atomic Fermi gas. The two atom species c
an have different hopping or mass. A very rich phase diagram for equal de
nsities of the species is found\, containing Mott insulators and superflui
ds. We also discuss coupling such 1D systems and the experimental signatu
res of the phases. In particular\, we compute the "spin"-structure factor
at small momentum\, which should reveal a "spin" gap.\n\n//indico.ictp.it
/event/a05391/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05391/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations:\n"T
he phase diagram of frustrated ladder models"\n
DTSTART;VALUE=DATE-TIME:20051208T100000Z
DTEND;VALUE=DATE-TIME:20051208T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a05397@ictp.it
DESCRIPTION:Using Density-Matrix Renormalization Group\, we investigate th
e general phase diagram of the frustrated two-leg ladder with Heisenberg i
nteractions along legs\, rungs and diagonals. We confirm that all antifer
romagnetic gapped states belong to the same universality class as the Hald
ane phase. In a three-dimensional phase diagram\, we determine a continuo
us surface with singularities in the string-order parameter or its first d
erivative\, corresponding to a transition between two Haldane phases with
different topological order.\n\n//indico.ictp.it/event/a05397/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a05397/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/Democritos Informal Seminar on Chemical Physics: "Carbo
nia: The amorphous silicalike carbon dioxide"\n
DTSTART;VALUE=DATE-TIME:20060124T103000Z
DTEND;VALUE=DATE-TIME:20060124T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a065@ictp.it
DESCRIPTION:Among the group IV elements\, carbon is the unique that at amb
ient condition forms stable double bonds with oxygen. In contrast to the c
ases of SiO2 and GeO2 the nonmolecular tetrahedral crystalline form of CO2
\, phase V\, only exists at high pressure. Similarly\, while the amorphous
phases of SiO2 (a-silica) and GeO2 (a-germania) are well known and stable
at room condition\, the amorphous\, nonmolecular\, phase of CO2\, althou
gh predicted by ab-initio simulations\, had not yet been discovered. We r
eport on the synthesis of amorphous\, silica-like\, carbon dioxide. The n
on molecular amorphous phase of carbon dioxide\, a-CO2\, that for similar
ity with other amorphous oxide of the group IV we will call 'a-carbonia'\,
was attained by compressing molecular phase III above 47 GPa at room temp
erature. In situ infrared spectra\, measured with raising temperature up
to 680 K\, probe the progressive formation of C-O single bonds and the sim
ultaneous disappearing of the molecular signatures. State-of-the-art Rama
n and synchrotron x-ray diffraction measurements on the temperature quench
ed sample show the amorphous character of this material. The comparison w
ith vibrational and diffraction patterns of amorphous silica and germania\
, shows that a-carbonia is homologous to those glasses. These findings do
extend the scenario of archetypal network-forming disordered systems such
as a-silica\, a-germania\, a-Si and a-Ge\, and water.\n\n//indico.ictp.it
/event/a065/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a065/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Disorder and strong electron correlations:\n"L
ocally accessible information and distillable entanglement"
DTSTART;VALUE=DATE-TIME:20060202T100000Z
DTEND;VALUE=DATE-TIME:20060202T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a067@ictp.it
DESCRIPTION:A different type of complementarity relation is found between
locally accessible information and final average entanglement for a given
ensemble. In some well known distillation protocols this complementary re
lation is optimally satisfied. There is some interesting trade off betwee
n locally accessible information and distilled entanglement for some state
s.\n\n//indico.ictp.it/event/a067/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a067/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Disorder and strong electron correlations: "Un
iversalities in electron scattering on mesoscopic obstacles"\n
DTSTART;VALUE=DATE-TIME:20060209T100000Z
DTEND;VALUE=DATE-TIME:20060209T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0617@ictp.it
DESCRIPTION:We study electron propagation through a random array of rare s
trong scatterers (e.g.\, quantum antidots) of geometrical sizes much grea
ter than the electron wavelength. It turns out that for a wide class of s
catterer's shapes\, the ratio of the transport and the total elastic scatt
ering rates does not depend on the scatterer's shape and is determined ent
irely by the space dimension. Possible experimental manifestations are di
scussed.\n\n//indico.ictp.it/event/a0617/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0617/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA/Democritos Condensed Matter Seminar: "Statistical
physics applied to the development of biopharmaceuticals"
DTSTART;VALUE=DATE-TIME:20060215T150000Z
DTEND;VALUE=DATE-TIME:20060215T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0618@ictp.it
DESCRIPTION:Biopharmaceuticals are globular protein or antibody drugs. It
is desired that they be formulated at high concentrations in aqueous solu
tions. However\, due to hydrophobic interactions and other effects\, thes
e molecules tend to aggregate in solution. Aggregation not only renders t
hese molecules inactive\, but also it can cause these molecules to be immu
nogenic\, one of the worst properties that a drug can have. Using fundame
ntal techniques from statistical physics\, we have developed a completely
new conceptual approach to tailor design additives to prevent aggregation
of these complex molecules. We have also performed some initial experime
ntal confirmations of our theories. In addition to the development of bio
pharmaceutical formulations\, our research has significance for understand
ing how living systems prevent protein aggregation and for understanding h
uman diseases such as Alzheimerâ€™s and Huntingtonâ€™s diseases.
\n\n//indico.ictp.it/event/a0618/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0618/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Disorder and strong electron correlations: ""S
pinless fermionic ladders in a magnetic field: Phase diagram"\n
DTSTART;VALUE=DATE-TIME:20060216T100000Z
DTEND;VALUE=DATE-TIME:20060216T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0620@ictp.it
DESCRIPTION:The system of interacting spinless fermions hopping on a two-l
eg ladder exhibits series of quantum phase transitions when subjected to e
xternal magnetic field. At half filling\, these are either U(1) Gaussian
phase transitions between two phases with distinct types of long-range ord
er or Berezinskii-Kosterlitz-Thouless transitions between ordered and gapl
ess phases.\n\n//indico.ictp.it/event/a0620/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0620/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and Strong Electron Correlations: "Mo
tt insulator-superfluid domains for confined BEC in optical lattices"\n\n
DTSTART;VALUE=DATE-TIME:20060223T100000Z
DTEND;VALUE=DATE-TIME:20060223T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0628@ictp.it
DESCRIPTION:Bose Einstein Condensates in optical lattices under an externa
l confinement are expected to form coexisting Superfluid and Mott-Insulati
ng domains [1] reminiscent of the quantum phase transition for the infinit
e system [2]. The experimentally observed transition [3] is presently asc
ribed to relative shrinking/widening of the different domains. The presen
ce of superfluid domains and the excitations of the interfaces between the
two phases play a crucial role in the time evolution of the system under
modulations of the parameters of the system as well as in its thermodynami
c properties. \nIn this work we derive the dispersion relation of the surf
ace waves at the interfaces between Mott-Insulating and Superfluid phases.
We then calculate their contribution to the heat capacity of the system
and show how its low temperature scaling allows a direct experimental test
of the existence and properties of Mott-Superfluid domains [4]. A furthe
r independent probe of the domains is considered studying the response of
the system to a periodic modulation of the intensity of the optical lattic
e. The induced parametric resonances of the superfluid excitations are re
flected in the energy absorption by the atomic cloud\, yielding informatio
n about the structure of different domains.\n\n[1] D. Jaksch et al. \, Phy
s. Rev. Lett. 81\, 3108 (1998) \n[2] M. P. A. Fisher et al. \, Phys. Rev.
B 40\, 546 (1989) \n[3] M. Greiner et al. \, Nature 415\, 39 (2002) \n[4]
E. Mariani and A. Stern\, Phys. Rev. Lett. 95\, 263001 (2005)\n\n//indico.
ictp.it/event/a0628/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0628/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations\n"Ko
ndo physics and strongly correlated superconductivity in model fullerene c
onductors"
DTSTART;VALUE=DATE-TIME:20060302T100000Z
DTEND;VALUE=DATE-TIME:20060302T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0632@ictp.it
DESCRIPTION:The effects of electronic correlations on superconductivity ar
e investigated by means of\nDynamical Mean Field Theory (DMFT) in a model
for alkali doped fullerenes. It is shown\nthat the proximity to a Mott tra
nsition amplifies the $s$-wave phonon-mediated pairing\nmechanism built in
to the model. It leads to a superconduting pocket adjacent the Mott\ninsul
ator with a large superconducting gap in comparison with the corresponding
BCS value.\nThe physical properties of this strongly correlated supercond
uctor are compatible with the\nexperimental data available on fullerenes.
Yet\, contradicting the common belief for fullerenes\,\nsuperconductivity
in the model is not of the BCS-type nor is the normal state a conventional
\nFermi-liquid. We find on the contrary several aspects which rather resem
ble those of\ncuprate superconductors\, such as an increase of Drude weigh
t accompaning the onset of\nsuperconductivity. We identify the origin of t
hese anomalies to the unconventional properties\ndisplayed by the Anderson
impurity model for a C$_{60}^{n-}$ molecule onto which the\nlattice model
maps within DMFT.\n\n//indico.ictp.it/event/a0632/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0632/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Disorder and strong electron correlations:\n"T
-duality in the supersymmetric theory of disordered quantum systems"
DTSTART;VALUE=DATE-TIME:20060309T100000Z
DTEND;VALUE=DATE-TIME:20060309T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0641@ictp.it
DESCRIPTION:Two variants of supermatrix field theory are discussed that de
scribe statistics of disordered quantum systems\, e.g. random matrix Hamil
tonians. One of them (nonlinear supersymmetric sigma model) is suitable f
or description of disordered systems with delocalized eigenfunctions and s
trongly correlated spectral statistics (disordered metals)\, the other is
convenient for systems with localized or quasi-localized eigenfunctions.
These two variants of theory are dual to each other but defined on the tar
get space of supermatrices with different symmetry ("T-duality"). An impl
ication of the symmetry difference for disordered one-dimensional single-a
nd multi-channel systems is discussed.\n\n//indico.ictp.it/event/a0641/
LOCATION:ICTP
URL://indico.ictp.it/event/a0641/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar: " Quantum information\,
measurements and their applications in molecular biology "
DTSTART;VALUE=DATE-TIME:20060315T150000Z
DTEND;VALUE=DATE-TIME:20060315T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0655@ictp.it
DESCRIPTION:The information-theoretical\, dynamical and statistical aspect
s of quantum measurements are reviewed. An example of dynamics of system
is considered which includes the measured object S\, the information stor
ing device O and its environment E. From the information-theoretical view
point\, the measurement is the transfer of information J from S to O with
the possible J losses\, due to O\,E decoherent interactions. Itâ€™s
shown that the principal constraints\, induced by Heisenberg commutation r
elations\, restrict significantly the amount of information J about S sta
te which can be transferred to O in the individual event. As a result an
ability of O to discriminate the different S states is much weaker compa
red to the predictions from the purely dynamical theory. Such restrictio
ns may explain experimentally observed stochasticity of measurement outcom
es\, i.e. the collapse of quantum state. The possible applications to mo
lecular biology\, bioelectronics and theory of brain functions are discuss
ed.\n\n//indico.ictp.it/event/a0655/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0655/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations\n"Qu
antum spin chain and O(3) non-linear sigma model with theta-term"
DTSTART;VALUE=DATE-TIME:20060316T100000Z
DTEND;VALUE=DATE-TIME:20060316T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0656@ictp.it
DESCRIPTION:Quantum anti-ferromagnetic chains admit a continuum formulatio
n in terms of O(3) non-linear sigma model with topological theta term. Th
e massive (theta=0) or massless (theta=pi) nature of this field theory is
referred in the literature as Haldane conjecture. Both values of theta c
orrespond to integrable model\, while for all other values the correspondi
ng theory is not integrable. In this talk we discuss the evolution of th
e spectrum by varying theta. We show that the massless particles (spinons
) present at theta=pi get confined once theta moves away from this value a
nd that the spectrum consists of a stable triplet of massive particles for
all values of theta and a singlet state of higher mass. The singlet\, ho
wever\, is a stable particle only in an interval of values of theta close
to pi\, whereas it becomes a resonance below a critical value theta_c.\n\n
//indico.ictp.it/event/a0656/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0656/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Statistical Physics: " The emergence of popula
rity: Statistical mechanics of movie income "\n
DTSTART;VALUE=DATE-TIME:20060324T130000Z
DTEND;VALUE=DATE-TIME:20060324T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0663@ictp.it
DESCRIPTION:Why do certain products/ideas become extremely popular\, while
other quite similar entities don't even make it off the mark? Can popula
rity be understood simply as a statistical phenomenon\, completely indepen
dent of the intrinsic quality of the product/idea? In this work\, we look
in detail at movie popularity\, analysing the income of movies released in
recent years\, in both USA and India. Our results offer interesting para
llels with popularity in other fields\, e.g.\, of scientific papers as mea
sured by citations. We conclude with discussion of models we have propose
d to explain various features of the observed movie popularity distributio
n.\n\n//indico.ictp.it/event/a0663/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0663/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations:\n"C
urrent division in parallel: A surprise"\n
DTSTART;VALUE=DATE-TIME:20060330T100000Z
DTEND;VALUE=DATE-TIME:20060330T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0670@ictp.it
DESCRIPTION:Consider some pieces of a wire of superconducting material hav
ing unequal lengths in general and connected in parallel. If\, now\, the
combination\, assumed to be in the normal state\, is connected to a dc cur
rent source\, the total current is known well to divide resistively. If\
, on the other hand\, the conductors were in the superconducting state\, t
he current is again known\, though less well now\, to divide inductively.
If\, however\, the combination of the current carrying conductors\, initi
ally in the normal state is cooled to and below the superconducting transi
tion temperature\, the current distribution is experimentally found to evo
lve towards equipartition. This indeed is a surprise. In this talk\, I wi
ll present our experimental findings\, and suggest a physical mechanism fo
r and a theoretical treatment of this self-organization of the current tow
ards equipartition on cooling through the transition.\n\n//indico.ictp.it/
event/a0670/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0670/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/Democritos\n\nInformal Seminar on Chemical Physics: "In
trinsic point defects in semiconductors: How the physics of a tiny entity
protrudes into the macroscopic world"\n
DTSTART;VALUE=DATE-TIME:20060331T100000Z
DTEND;VALUE=DATE-TIME:20060331T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0674@ictp.it
DESCRIPTION:Intrinsic point defects in semiconductor represent the smalles
t conceivable perturbation of the ideal crystal lattice. These omnipresen
t defects display appealing physical properties that have important techno
logical implications. Intrinsic point defects possess localized states de
ep within the band gap and can compensate dopants thus effecting the elect
ronic properties of a material. The ground state of vacancies (empty latti
ce sites)\, for example\, is governed by a competition between th electron
-electron interaction and electron-phonon coupling\, eventually resulting
in a competion between a "high-spin''\, high symmetry o a "low spin''\,
Jahn-Teller distorted ground state. On the other hand intrinsic defects a
re mobile and can diffuse through the material. They are thus pivotal for
the mass transport and for the annealing of processed material. The talk
will illustrate these aspects for intrinsic defects in Silicon Carbide fr
om the theoretical point of view. Emphasis is also put on the link to rec
ent experimental work that enabled together with theoretical efforts an id
entification of individual defects.\n\n//indico.ictp.it/event/a0674/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0674/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and Strong Electron Correlations:\n"F
luxoid states and oscillations of the Josephson current in low-dimensional
weak"
DTSTART;VALUE=DATE-TIME:20060406T100000Z
DTEND;VALUE=DATE-TIME:20060406T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0678@ictp.it
DESCRIPTION:I will discuss charge transport in a specific type of low-dime
nsional normal metal (N)-superconductor (S) systems which can exhibit near
ly reflectionless tunneling of Cooper pairs even for low-transparency inte
rfaces. In SNS structures such reflectionless tunneling results in anomal
ous Andreev bound states that make a dominant contribution to the Josephso
n current. An interesting situation occurs in systems with multiply connec
ted superconductors where the Andreev bound states are coupled to an exter
nal magnetic flux via the fluxoid quantization. In this case magnetic osc
illations of the critical Josephson current analogous to the Little-Parks
effect are predicted. I will also discuss experiments presumably demonstr
ating the reflectionless tunneling of Cooper pairs.\n\n//indico.ictp.it/ev
ent/a0678/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0678/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and Strong Electron Correlations:\n"T
he challenge of error correction in quantum computation"\n
DTSTART;VALUE=DATE-TIME:20060420T100000Z
DTEND;VALUE=DATE-TIME:20060420T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0694@ictp.it
DESCRIPTION:I compare the software approach to the error correction in qua
ntum computation to the hardware one in which the protection from errors i
s due to a proper choice of the microscopic Hamiltonian. I show that from
the theoretical point of view the systems protected at the physical level
are characterized by the topological order parameter. I argue that neithe
r the software correction nor this topological protection alone can be suf
ficient to achieve a stable computation with today technology. The most p
romising approach seems to combine some level of hardware error correction
that can be achieved in mesoscopic physical systems characterized by topo
logical order parameter with the software error correction at a higher lev
el. I review the simplest spin models and the small size Josephson juncti
on arrays that provide this protection and discuss the requirements on the
m imposed by the software error correction.\n\n//indico.ictp.it/event/a069
4/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0694/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations\n"El
ectronic properties of graphene and graphitic bilayers"
DTSTART;VALUE=DATE-TIME:20060425T100000Z
DTEND;VALUE=DATE-TIME:20060425T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0697@ictp.it
DESCRIPTION:Electrons in graphitic monolayers (graphene) and bilayers have
very unusual properties: these are chiral quasiparticles which are chara
cterized by the Berry phase Pi (in graphene) and 2Pi (in a bilayer). The
chirality of quasiparticles manifests itself in a peculiar Landau level sp
ectrum and in the form of the quantum Hall effect. It also generates speci
fic quantum transport characteristics\, such as selective transmission and
magneto-resistance in ballistic n-p junctions in graphene\, and it gives
rise to a rich variety of weak localisation regimes in a monolayer and a b
ilayer.\n\n//indico.ictp.it/event/a0697/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0697/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations: \n"
Minigap in superconductor-ferromagnet junctions with inhomogenous magnetiz
ation"\n\n
DTSTART;VALUE=DATE-TIME:20060427T100000Z
DTEND;VALUE=DATE-TIME:20060427T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0698@ictp.it
DESCRIPTION:We consider the minigap in a disordered ferromagnet (F) in con
tact with a superconductor (S) in the situation when the magnetization of
the F is inhomogeneous in space and noncollinear. If the magnetization i
s strongly inhomogeneous\, it effectively averages out\, and the minigap s
urvives up to the exchange field $h_c ~ (L/a) E_{Th}$\, where $L$ is the t
hickness of the F\, $a$ is the scale on which the magnetization varies\, a
nd $E_{Th}$ is the Thouless energy. Technically\, we use the "triplet" ve
rsion of the Usadel equations including both singlet and triplet component
s of the Green's functions. In many cases\, the effect of disordered magne
tization may be effectively included in the conventional Usadel equations
as the spin-flip scattering term. In the case of low-dimensional magnetic
inhomogeneities (we consider spiral magnetization as an example)\, howeve
r\, the full set of "triplet" equations must be solved.\n\n//indico.ictp.i
t/event/a0698/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a0698/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and Strong Electron Correlations:\n"H
ow to have fun with two-dimensional frustrated ferromagnets..."\n
DTSTART;VALUE=DATE-TIME:20060504T100000Z
DTEND;VALUE=DATE-TIME:20060504T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06106@ictp.it
DESCRIPTION:The theoretical study of two-dimensional "spin liquids'' ---
quantum magnets which remain disordered at the very lowest temperatures -
-- has mostly been confined to models with competing or frustrated antifer
romagnetic (AF) interactions. The resulting ground states typically involv
e strong singlet bonds between spins\, which give rise to a gap in the spi
n excitation spectrum. None the less\, the best characterized experimenta
l realization of a spin liquid is believed to occur in two--dimensional fi
lms of solid $^3$He\, where the interactions between spins are predominant
ly ferromagnetic (FM)\, and the resulting state is gapless. Here we consi
der whether the breakdown of long ranged FM order offers a new route uncon
ventional magnetic ground states in two dimensions\, considering in detail
the case of the square lattice frustrated ferromagnet.\n\n//indico.ictp.i
t/event/a06106/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a06106/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar: "Kondo effect in real l
ife"
DTSTART;VALUE=DATE-TIME:20060510T150000Z
DTEND;VALUE=DATE-TIME:20060510T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06111@ictp.it
DESCRIPTION://indico.ictp.it/event/a06111/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a06111/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Chemical Physics: "Inelastic X-ray scattering
from phonons at high pressure"\n
DTSTART;VALUE=DATE-TIME:20060516T130000Z
DTEND;VALUE=DATE-TIME:20060516T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06117@ictp.it
DESCRIPTION:Since the first pioneering experiments in the late 1980â€
™s\, inelastic X-ray scattering (IXS) with meV energy resolution has evo
lved rapidly into a valuable spectroscopic tool to study phonon dispersion
in a large variety of materials. IXS is particularly well suited for dis
ordered systems\, samples only available in small quantities\, or material
s studied under very high pressure. Thanks to the outstanding brilliance
of third generation synchrotron sources and performing focusing X-ray opti
cs\, phonon studies to 50 GPa and beyond are nowadays routinely performed.
The present capabilities of IXS shall be illustrated by selected example
s of high-pressure work.\n\n//indico.ictp.it/event/a06117/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a06117/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and Strong Electron Correlations:\n"T
he interplay of spin and charge channels \nin zero dimensional system"\n
DTSTART;VALUE=DATE-TIME:20060518T100000Z
DTEND;VALUE=DATE-TIME:20060518T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06118@ictp.it
DESCRIPTION:We consider the interplay of the charge and spin zero-mode int
eractions in quantum dots. The non-perturbative effects of zero-mode inte
raction are described in terms of the propagation of gauge bosons associat
ed with charge (U(1)) and spin (SU(2)) fluctuations in the dot. The Coul
omb and longitudinal spin components are accounted for exactly\, while tra
nsverse spin fluctuations are studied perturbatively (with the easy-axis
anisotropy). These fluctuations become important as one approaches the St
oner instability. We study the influence of spin on the differential cond
uctance as well as the dynamic spin susceptibility.\n\n//indico.ictp.it/ev
ent/a06118/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a06118/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations "Tr
iplet pairing due to spin-orbit-assisted electron-phonon coupling"\n
DTSTART;VALUE=DATE-TIME:20060525T100000Z
DTEND;VALUE=DATE-TIME:20060525T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06122@ictp.it
DESCRIPTION:We propose a microscopic mechanism for triplet pairing due to
spin-orbit-assisted electron interaction with optical phonons in a crystal
with a complex unit cell. Using two examples of electrons with symmetric
Fermi surfaces in crystals with either a cubic or a layered square lattic
e\, we show that spin-orbit-assisted electron-phonon coupling can\, indeed
\, generate triplet pairing and that\, in each case\, it predetermines the
tensor structure of a p-wave order parameter.\n\n//indico.ictp.it/event/a
06122/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a06122/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter seminar: "Mesoscopic thermodynam
ics and coupled ordering in soft matter" \n
DTSTART;VALUE=DATE-TIME:20060526T100000Z
DTEND;VALUE=DATE-TIME:20060526T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06124@ictp.it
DESCRIPTION:Thermodynamics is a keystone in science and engineering\, brid
ging the gap between fundamentals and applications. However\, engineers
often have to design processes and products where classical thermodynamics
may become insufficient\, e.g.\, strongly fluctuating and nanosize system
s\, or dissipative systems under conditions far away from equilibrium. A
new field\, â€œmesoscopic thermodynamicsâ€ can be defined as a se
mi-phenomenological approach to the systems and phenomena in which a lengt
h - intermediate between the atomistic scale and the macroscopic scale - e
merges and where such a length explicitly affects thermodynamic properties
. Finite-size effects and fluctuations\, critical phenomena and spinodal
decomposition\, wetting and interfacial phenomena\, self-organized critica
lity and guided self-assembly\, thermodynamics of pattern formation and fr
actals are examples of the topics addressed in mesoscopic thermodynamics.
While conventional methods of statistical mechanics remain to be the fund
amental background of mesoscopic thermodynamics\, â€œcoarse-grainedâ
€ approaches\, such as the Landau-Ginzburg local free-energy functiona
l\, can be successfully applied for describing apparently very different p
henomena on mesoscales - from critical fluctuations to interfacial profile
s\, from porous media to micelles and microemulsions. These approaches em
phasize universality and utilize a number of powerful theoretical concepts
\, such as renormalization-group theory\, finite-size scaling\, and percol
ation theory. A coupling between different order parameters is ubiquitous
in soft matter. At meso and nano scales\, coupling between order paramet
ers is associated with competition between different correlation lengths a
nd may result in coupled dynamics of fluctuations. As an example\, I will
discuss coupled mesoscopic dynamics (â€œavoided crossingâ€) caus
ed by competition between mesoscales in near-critical polymer solutions.
Similar phenomena are expected in a broad range of soft-matter materials a
s gels\, microemulsions\, and lyotropic liquid crystals\, wherever critica
l fluctuations may couple with the mesoscopic structure.\n\n//indico.ictp.
it/event/a06124/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a06124/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations\n"A
fuzzy description of Quantum Hall Physics"\n
DTSTART;VALUE=DATE-TIME:20060601T100000Z
DTEND;VALUE=DATE-TIME:20060601T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06125@ictp.it
DESCRIPTION:Noncommutative Chern-Simons action has been proposed as an eff
ective description of the dynamics of infinite Quantum Hall samples projec
ted into the lowest Landau level. A special kind of regularization of thi
s model gives rise to a matrix Chern-Simons theory\, that can be used to d
escribe finite droplets. I will try to give a self-contained and physical
ly motivated introduction to both noncommutative Chern-Simons theory and i
ts matrix version\, and their application to Fractional Quantum Hall Effe
ct.\n\n//indico.ictp.it/event/a06125/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a06125/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar: "Possible exact thresho
ld for toric code of quantum memory" \n
DTSTART;VALUE=DATE-TIME:20060614T100000Z
DTEND;VALUE=DATE-TIME:20060614T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06133@ictp.it
DESCRIPTION:The error threshold of toric code\, beyond which the stored qu
antum state deteriorates\, is closely related to the multicritical point o
f the 2d spin glass. It is thus important to accurately determine the lo
cation of the multicritical point of 2d spin glass systems. We have devel
oped a scheme to solve this problem\, which is likely to give the exact r
esults\, using duality arguments.\n\n//indico.ictp.it/event/a06133/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a06133/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Statistical Physics: "Mean exit times and surv
ival probability of equity assets"
DTSTART;VALUE=DATE-TIME:20060614T150000Z
DTEND;VALUE=DATE-TIME:20060614T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06134@ictp.it
DESCRIPTION:We study theoretical and empirical aspects of the mean exit ti
me of financial time series. The theoretical modeling is done within the f
ramework of continuous time random walk. We empirically verify that the m
ean exit time follows a quadratic scaling law and it has associated a pre-
factor which is specific to the analyzed stock. We perform a series of st
atistical tests to determine which kind of correlation are responsible for
this specificity. The main contribution is associated with the autocorre
lation property of stock returns. We introduce and solve analytically bot
h a two-state and a three-state Markov chain models. The analytical resul
ts obtained with the two-state Markov chain model indicate the possibility
of obtaining a data collapse of the measured MET profiles in a single mas
ter curve.\n\n//indico.ictp.it/event/a06134/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a06134/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar: "Orbital densities func
tional"
DTSTART;VALUE=DATE-TIME:20060912T150000Z
DTEND;VALUE=DATE-TIME:20060912T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06268@ictp.it
DESCRIPTION:Local density approximation (LDA) to density functional theory
(DFT) has continuous derivative of total energy as a number of electrons
function and continuous exchange-correlation potential\, while in exact DF
T both should be discontinuous as number of electrons goes through an inte
ger value. We propose orbital densities functional (ODF) (with orbitals d
efined as Wannier functions) that by construction obeys this discontinuity
condition. By its variation one-electron equations are obtained with pot
ential in the form of projection operator. The operator increases a separ
ation between occupied and empty bands thus curing LDA deficiency of energ
y gap value systematic underestimation. Orbital densities functional mini
mization gives ground state orbital and total electron densities. The ODF
expression for energy of orbital densities fluctuations around the ground
state values defines ODF fluctuation Hamiltonian that allows to treat cor
relation effects. Dynamical mean-field theory (DMFT) was used to solve th
is Hamiltonian with quantum Monte Carlo (QMC) method for effective impurit
y problem. We have applied ODF method to the problem of metal insulator t
ransition in lanthanum trihydride LaH{3-x}. In LDA calculations ground sta
te of this material is metallic for all values of hydrogen non-stoichiomet
ry $x$ while experimentally the system is insulating for x\n\n//indico.ict
p.it/event/a06268/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a06268/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations:\n"S
emi-linear response\, the absorption of radiation by small metal grains\,
and the conductance of mesoscopic devices"
DTSTART;VALUE=DATE-TIME:20060914T100000Z
DTEND;VALUE=DATE-TIME:20060914T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06271@ictp.it
DESCRIPTION:Consider a driven quantum system\, such as a small conducting
particle driven by an electromagnetic radiation\, or a mesoscopic ring dri
ven by an electromotive force. The common practice is to calculate the re
sponse (rate of energy absorption\, conductance) using the Kubo Formula.
We argue that this may lead to a huge over-estimate. In general it is ess
ential to take into account the structure of the perturbation matrix\, whi
ch may imply percolation-like dynamics. These structures are determined b
y both semiclassical and random matrix theory consideration\, and cannot b
e ignored.\n\n//indico.ictp.it/event/a06271/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a06271/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Disorder and strong electron correlations:\n"
'Massive neutrinos' in graphene "
DTSTART;VALUE=DATE-TIME:20061010T100000Z
DTEND;VALUE=DATE-TIME:20061010T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06293@ictp.it
DESCRIPTION:We study interacting Dirac quasiparticles in graphene\, focusi
ng on such experimentally relevant issues as a dynamically generated mass
due to unscreened Coulomb interactions\, (anti)localization in the presen
ce of disorder\, and anomalous Quantum Hall effect.\n\n//indico.ictp.it/ev
ent/a06293/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a06293/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Statistical Physics: " Path to synchronization
in complex networks "
DTSTART;VALUE=DATE-TIME:20061011T100000Z
DTEND;VALUE=DATE-TIME:20061011T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06292@ictp.it
DESCRIPTION:We study the synchronizability of complex networks whose degre
e distributions are Poisson or heavy tailed (scale-free). Our analysis is
based on the dynamics of the Kuramoto's model in a system of coupled osci
llators that interact in these topologies. We investigate the evolution o
f patterns of synchronized oscillators\, and connect this local informatio
n with global measures of synchronization in the system. The results show
that\, there are values for the intensity of the interaction that make de
gree homogeneous networks more synchronizable than heterogeneous networks
and vice-versa. Moreover\, we study the synchronization transition in sca
le-free networks that are characterized by tunable local properties. Our
study highlights the need of exploring the whole phase diagram and not onl
y the stability of the fully synchronized state\, where most studies have
been done up to now.\n\n//indico.ictp.it/event/a06292/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a06292/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Diversity begets stabili
ty in an evolutionary model"\n
DTSTART;VALUE=DATE-TIME:20061018T100000Z
DTEND;VALUE=DATE-TIME:20061018T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06303@ictp.it
DESCRIPTION://indico.ictp.it/event/a06303/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a06303/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Statistical Physics: "Time scales in evolution
ary dynamics"
DTSTART;VALUE=DATE-TIME:20061019T100000Z
DTEND;VALUE=DATE-TIME:20061019T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06304@ictp.it
DESCRIPTION:A fundamental\, profound and broad-ranging unsolved question i
s how cooperation among animals and humans has evolved. Evolutionary game
theory is the mathematical framework that has provided the deepest insigh
ts into this issue. Simple games such as the Prisoners' Dilemma\, the sno
wdrift game or the stag-hunt game have been the subject of intense experim
ental and theoretical work along this line\, but no previous approach has
considered the influence of different evolution rates.\nHere we show that
the pace at which selection acts on the population is crucial for the appe
arance and stability of cooperation. Even in non-dilemma games such as Har
mony\, where cooperation is the only possible rational outcome\, defectors
may be selected for if population renewal is very rapid. We carry out a t
horough study of the different types of 2x2 symmetrical games and find tha
t unexpected results arise in all three cases. We discuss the nature of th
e changes induced by the time scale competition and point out the necessit
y to include a discussion of the time scale of evolution in any study abou
t cooperation.\n\n//indico.ictp.it/event/a06304/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a06304/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar: "Theory of enhanced the
rmoelectric performance in strongly correlated multilayered nanostructures
"
DTSTART;VALUE=DATE-TIME:20061025T150000Z
DTEND;VALUE=DATE-TIME:20061025T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06311@ictp.it
DESCRIPTION:We illustrate how the electronic charge reconstruction near th
e interfaces of metal/strongly-correlated barrier/metal devices can lead
to a significant enhancement of the thermoelectric response due to the b
reaking of particle-hole symmetry. We show how one can achieve effective
Seebeck coefficients larger than 150 μV/K and effective electronic figure
s-of-merit ZT higher than 1. Our theory shows that electronic thermoelect
ric transport properties can be significantly enhanced from inhomogeneitie
s created by the rearrangement of charge near the interfaces\, and that bu
lk figures-of-merit cannot generically be employed to determine the figure
-of-merit of a multilayered nanostructure.\n\n//indico.ictp.it/event/a063
11/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a06311/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations:" No
n-equilibrium critical behaviours in driven diffusive systems "\n
DTSTART;VALUE=DATE-TIME:20061026T100000Z
DTEND;VALUE=DATE-TIME:20061026T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06306@ictp.it
DESCRIPTION:Many physical systems in equilibrium undergo phase transitions
when the external control parameters (such as temperature\, pressure\, et
c) approach certain values. Among these transitions\, critical phenomena
are characterized by an emerging collective behaviour - on a scale much l
arger than the microscopic one - and by a certain degree of universality:
different physical systems may display the same critical behaviour. This
allows one to study such phenomena via extremely simplified models. The
lattice gas (equivalent to the Ising model) was introduced to study the li
quid-vapour transition and played a primary role in the development of the
theory of equilibrium phase transitions and collective critical phenomena
.\nIn this talk I discuss how the critical behaviour of the lattice gas is
affected by those external forces which drive the model into non-equilibr
ium steady states.\n\n//indico.ictp.it/event/a06306/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a06306/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations\n"Bo
sonization approach to charge and spin dynamics of 1D fermions"\n
DTSTART;VALUE=DATE-TIME:20061102T100000Z
DTEND;VALUE=DATE-TIME:20061102T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06316@ictp.it
DESCRIPTION:The dynamics of fermions in clean quantum wires are generally
described by the low-energy Tomonaga-Luttinger model which assumes forward
scattering interactions and a linearized dispersion: $\\xi_k = v(|k|-k_F
)$\, around the Fermi points $\\pm k_F$. This model can be solved exactly
with the help of the bosonization technique which maps the low-energy int
eracting fermions to free bosons. At these low-energies the dynamics of sp
in and charge excitations are separated and dissipation-less. In this talk
some higher-energy features of the dynamics will be explored with the hel
p of bosonization by taking into account band-curvature corrections to the
spectrum: $\\xi_k = v(|k|-k_F) + (|k|-k_F)2/2m$. The latter lead to inter
actions between the low-energy bosons which are crucial to the description
of the precise line-shape of dynamical correlators (in relation with plas
mon life-time and optical fermion conductivity). I will show how this no
n-linear bosonization can be implemented\, discuss its efficiency and limi
tations and finally give signatures of spin-charge coupling due to band-cu
rvature on dynamical correlation functions. The latter could be observed e
xperimentally via energy and momentum resolved spectroscopies.\n\n//indico
.ictp.it/event/a06316/
LOCATION:ICTP Main Building Room 239
URL://indico.ictp.it/event/a06316/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Statistical Physics: "Statistical physics appr
oach to models of risk"
DTSTART;VALUE=DATE-TIME:20061108T100000Z
DTEND;VALUE=DATE-TIME:20061108T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06317@ictp.it
DESCRIPTION:We look at the problem of estimating risk (Operational Risk\,
Credit Risk and Market Risk) and argue that risk elements\, such as proces
ses in an organization\, credits in a loan-portfolio or share prices in a
n investment portfolio cannot be regarded as independent. This naturally l
eads to formulating risk models as dynamical models of interacting degrees
of freedom (particles). The operational risk and credit risk problems ca
n be cast into a language describing heterogeneous lattice gasses\, in whi
ch interaction parameters and non-uniform chemical potentials have an inte
rpretation in terms of unconditional and conditional failure probabilities
. For the market risk problem\, a minimal interacting generalization of t
he classical Geometric Brownian Motion model leads to a formulation of mar
ket dynamics that is formally similar to the dynamics of graded response n
eurons. We describe elements of the statistical mechanical analysis of th
ese models to reveal their macroscopic properties.\n\n//indico.ictp.it/eve
nt/a06317/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a06317/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Gaussian-to-Lévy statis
tical crossover in a random amplifying medium"
DTSTART;VALUE=DATE-TIME:20061117T100000Z
DTEND;VALUE=DATE-TIME:20061117T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06332@ictp.it
DESCRIPTION:We have studied the emission from Random Amplifying Media (RAM
) by means of experiments\, theoretical analysis and Monte Carlo simulatio
n. We report the crossover from the Gaussian to the Lévy statistics in t
he ﬂuctuation of emission intensity from RAM and demonstrate the tunabil
ity of Lévy exponent.\nIn order to examine the competition between the sc
attering and the gain\, we studied by Monte Carlo simulation\, the emissio
n from conventional dye scatterer systems and the reverse case of active s
catterers suspended in a passive bulk. The marked difference in their emis
sion features\, especially at high scatterings\, lead us to classify them
as the Direct RAM (D RAM) and the Reverse RAM (R RAM) respectively.\n\n//i
ndico.ictp.it/event/a06332/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a06332/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations:\n"O
ne-dimensional fermions beyond the Luttinger liquid paradigm"
DTSTART;VALUE=DATE-TIME:20061123T100000Z
DTEND;VALUE=DATE-TIME:20061123T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06334@ictp.it
DESCRIPTION:In this presentation I will review our recent work on dynamic
correlations in a system of one-dimensional fermions with a nonlinear disp
ersion. It turns out that in the presence of interactions the nonlinear d
ispersion results in new universal features in the frequency and the wave
vector dependence of the dynamic structure factor (density-density correla
tion function). These features are similar in origin to the well-known Fer
mi-edge singularities in the X-ray absorption spectra of metals. Besides
being of interest for its own sake\, detailed understanding of the struct
ure factor is crucial for the description of a variety of transport phenom
ena that owe their existence to the particle-hole asymmetry\, such as Coul
omb drag\, thermopower\, and photovoltaic effect\, as well as for the desc
ription of inelastic neutron scattering off antiferromagnetic spin chains.
\n\n//indico.ictp.it/event/a06334/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a06334/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/Democritos Informal Seminar on Chemical Physics\n"Lifti
ng of IR {100} reconstruction by CO adsorption: An ab initio study"\n
DTSTART;VALUE=DATE-TIME:20061128T100000Z
DTEND;VALUE=DATE-TIME:20061128T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06340@ictp.it
DESCRIPTION:The adsorption of CO on unreconstructed and reconstructed Ir{
100} has been studied\, using a combination of density functional theory
and thermodynamics\, to determine the relative stability of the two phase
s as a function of CO coverage\, temperature and pressure. We obtain g
ood agreement with experimental data. At zero temperature\, the (1X5) rec
onstruction becomes less stable than the unreconstructed (1X1) surface w
hen the CO coverage exceeds a critical value of 0.09 ML. The interaction
between CO molecules is found to be repulsive on the reconstructed surfac
e\, but attractive on the unreconstructed\, explaining the experimental ob
servation of high CO coverage on growing (1X1) islands. At all temperatur
es and pressures\, we find only two possible stable states: 0.05 ML CO
c(2X2) overlayer on the (1X1) substrate\, and the clean (1X5) reconstruc
ted surface.\n\n//indico.ictp.it/event/a06340/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a06340/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Seminar: "Some open issues pertinent to the pheno
menon of dynamical scaling of structure factor"
DTSTART;VALUE=DATE-TIME:20061129T150000Z
DTEND;VALUE=DATE-TIME:20061129T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06339@ictp.it
DESCRIPTION:The phenomenon of new phase formation is a representative exam
ple of first order transition. The phenomenon is fundamental and of immens
e interest as an example of a highly nonlinear process far from equilibriu
m. The second phase grows with time and in late stages all domain sizes ar
e much larger than all microscopic lengths. In the large time limit\, the
new phase forming systems exhibit self-similar growth pattern with dilatio
n symmetry\, with time dependent scale\, and scaling phenomenon. The pheno
menon is indicative of the emergence of a morphological pattern of the dom
ains at earlier times looking statistically similar to a pattern at later
times apart from the global change of scale implied by the growth of time
dependent characteristic length scale L(t) – a measure of the time depen
dent domain size of the new phase.\nThe scaling hypothesis assumes the exi
stence of a single characteristic length scale L(t) such that the domain s
izes and their spatial correlation are time invariant when the lengths are
scaled by L(t). Quantitatively\, for isotropic systems\, the equal-time s
patio-temporal composition modulation auto-correlation function g(r\,t)\,
reflects the way in which the mean density of the medium varies as a funct
ion of distance from a given point\, should exhibit the scaling form with
time-dependent dilation symmetry g(r\,t)=f(r/L(t)). The scaling function f
(r/L(t)) is universal in the sense that it is independent of initial condi
tions and also on interactions as long as they are short ranged. However\,
form of f(r/L(t)) depends non-trivially on n\, the number of components i
n the vector order-parameter field exhibiting the scaling behavior\, and d
\, the dimensionality of the system. It is important to note that the scal
ing hypothesis has not been proved conclusively except for some model syst
ems. Based on some of our recent observations [1-4]\, we propose to reexa
mine the extent of validity of scaling laws addressing issues like (i) uni
queness of characteristic length L(t)\; (ii) the extent of validity of the
scaling laws for new phase formation in the case of non-Euclidean fractal
systems\; (iii) the extent of validity of the scaling laws for multicompo
nent systems.\n \nReferences\n[1] S. Mazumder\, et al.\, Phys. Rev. B 60
(1999) 822.\n[2] S. Mazumder\, et al.\, Phys. Rev. Lett 93 (2004) 255704.
\n[3] S. Mazumder\, et al.\, Phys. Rev. B 72 (2005) 224208.\n[4] S. Mazumd
er\, Physica B\, in press.\n\n//indico.ictp.it/event/a06339/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a06339/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Disorder and strong electron correlations\n"Th
e emptiness formation probability: Going beyond the Luttinger liquid model
"\n
DTSTART;VALUE=DATE-TIME:20061130T100000Z
DTEND;VALUE=DATE-TIME:20061130T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06341@ictp.it
DESCRIPTION:The Emptiness Formation Probability (EFP) is a very important
correlation function in the theory of integrable models. In One-Dimension
\, it measures the probability that a region of length n will present no p
articles. For spin chains\, the Jordan-Wigner transformation maps the EFP
into the Probability of Formation of Ferromagnetic Strings (PFFS)\, i.e.
the probability that a string of n spins are all aligned in one direction.
The configuration measured by the EFP is in general very different from
the equilibrium one. Because of this\, the EFP is an ideal example of a c
orrelator that cannot be captured by a bosonization approach\, since it re
quires contributions from the whole spectrum of the system. In the first
part of the talk\, we will present an alternative (exact) way to calculat
e the EFP for the anisotropic XY model at zero temperature\, by representi
ng this correlator as the determinant of a Toeplitz matrix. Using the lit
erature on Toeplitz determinants\, we will be able to calculate the asympt
otic behavior of the EFP in the different regions of the phase diagram of
the XY model. In the second part of the talk\, we will introduce a hydrod
ynamic description of integrable models at zero temperature\, that will al
low us to calculate the EFP for simple systems. This hydrodynamic approac
h is a collective description of the system that takes naturally into acco
unt the curvature of the spectrum\, at the cost of dealing with a non-line
ar theory. This approach could be used to describe other effects beyond t
he Luttinger Liquid model\, for instance the higher energy corrections to
the exact Spin-Charge separation prediction for low-lying excitations.\n\n
//indico.ictp.it/event/a06341/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a06341/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar: "Eigenfunction fractality and pseudogap state n
ear superconductor-insulator transition"
DTSTART;VALUE=DATE-TIME:20061206T150000Z
DTEND;VALUE=DATE-TIME:20061206T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06347@ictp.it
DESCRIPTION:We develop a theory of a pseudogap state appearing near the su
perconductor-insulator transition\nin strongly disordered metals with attr
active interaction. We show that such an interaction\, combined\nwith the
fractal nature of the single particle wave functions near the mobility edg
e\, leads to an\nanomalously large single particle gap in the superconduct
ing state near SI transition that persists \nand even increases in the ins
ulating state long after the superconductivity is destroyed. We give\nanal
ytic expressions for the value of the pseudogap in terms of the inverse pa
rticipation ratio of the\ncorresponding localization problem.\n\n//indico.
ictp.it/event/a06347/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a06347/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar on: \n"Phenomenological
theory of underdoped state of the cuprates "\n
DTSTART;VALUE=DATE-TIME:20061213T150000Z
DTEND;VALUE=DATE-TIME:20061213T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06352@ictp.it
DESCRIPTION:We model the Fermi surface of the cuprates by 1D nested parts
near the antinodal regions and unnested parts near the zone diagonals. El
ectrons in the nested regions form 1D spin liquids and develop spectral ga
ps below some T*\, but superconducting order is prevented by quantum fluct
uations. It is shown that Josephson coupling between order parameters for
med at antinodes locks their relative phase at a crossover scale T** \n\n
//indico.ictp.it/event/a06352/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a06352/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Disorder and strong electron correlations\n" E
lectron fractionalization in two-dimensional graphene-like structures "\n
DTSTART;VALUE=DATE-TIME:20061214T100000Z
DTEND;VALUE=DATE-TIME:20061214T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a06351@ictp.it
DESCRIPTION:Electron fractionalization is intimately related to topology.
In one-dimensional systems\, fractionally charged states exist at domain
walls between degenerate vaccua. In two-dimensional systems\, fractionali
zation exists in quantum Hall fluids\, where time-reversal symmetry is bro
ken by a large external magnetic field. Recently\, there has been a treme
ndous effort in the search for examples of fractionalization in two-dimens
ional systems with time-reversal symmetry. In this paper\, we show that f
ractionally charged topological excitations exist on graphene-like structu
res\, where quasiparticles are described by two flavors of Dirac fermions
and time-reversal symmetry is respected. The topological zero-modes are m
athematically similar to fractional vortices in p-wave superconductors. T
hey correspond to a twist in the phase in the mass of the Dirac fermions\,
akin to cosmic strings in particle physics.\n\n//indico.ictp.it/event/a06
351/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a06351/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:\n"Kondo shut
tling in nanoelectromechanical devices"\n
DTSTART;VALUE=DATE-TIME:20070201T100000Z
DTEND;VALUE=DATE-TIME:20070201T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0717@ictp.it
DESCRIPTION:We investigate theoretically a mechanically assisted Kondo eff
ect and electric charge shuttling in nanoelectromechanical single-electron
transistor (NEM-SET) charged by odd/even number of electrons. It is sho
wn that the mechanical motion of mobile quantum impurity with the spin res
ults in the time dependent tunneling width which leads to effective increa
se of the Kondo temperature. The time-dependent oscillating Kondo tempera
ture changes the scaling behavior of the differential conductance resultin
g in the suppression of transport in a strong coupling- and its enhancemen
t in a weak coupling regimes. The conditions for fine-tuning of the Abriko
sov-Suhl resonance and possible experimental realization of the Kondo shut
tling in a spin pumping regime are discussed.\n\n//indico.ictp.it/event/a0
717/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a0717/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Towards an understanding of transport through junctions in quantum
-Hall systems
DTSTART;VALUE=DATE-TIME:20070208T100000Z
DTEND;VALUE=DATE-TIME:20070208T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0725@ictp.it
DESCRIPTION:Motivated by recent experimental findings (e.g.\, PRL 95\, 156
804 (2005))\, we study transport in a simple phenomenological model of a q
uantum Hall edge system with a gate-voltage controlled constriction loweri
ng the local filling factor. The current backscattered from the constricti
on is seen to arise from the matching of the properties of the edge-curren
t excitations in the constriction ν2 and bulk ν1 regions. We develop a
hydrodynamic theory for bosonic edge modes inspired by this model\, findin
g that a competition between two tunneling process\, related by a quasipar
ticle-quasihole symmetry\, determines the fate of the low-bias transmissio
n conductance. In this way\, we find satisfactory explanations for many re
cent puzzling experimental results.\n\n//indico.ictp.it/event/a0725/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0725/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"Cooper inst
ability near the Anderson transition"
DTSTART;VALUE=DATE-TIME:20070215T100000Z
DTEND;VALUE=DATE-TIME:20070215T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0728@ictp.it
DESCRIPTION:We consider the simplest model of a disordered superconductor
in which electron interaction is attractive near the Fermi surface and the
Coulomb repulsion is absent. In contrast to classical BCS theory we assu
me the multifractal statistics of near critical one-particle eigenstates n
ear the Anderson transition. Using different approximations for the tempe
rature of Cooper instability and generating the multifractal states from t
he corresponding random-matrix ensembles we find this temperature to be dr
astically increased at the Anderson transition and behaving like a power 1
/(1-D_2/3)~1.6 of the dimensionless attraction constant. Here D_2 is the
correlation fractal dimension of the single-particle eigenfunction which f
or the 3D Anderson model is approximately equal to 1.3. We also study the
superconducting temperature as a function of the localization-correlation
length in the vicinity of the Anderson transition and show that the super
conductivity persists in the Anderson insulator until the level spacing in
the localization volume becomes of the order of the critical temperature
exactly at the transition.\n\n//indico.ictp.it/event/a0728/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a0728/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar on: "Mapping spin struct
ures on the atomic scale"
DTSTART;VALUE=DATE-TIME:20070221T150000Z
DTEND;VALUE=DATE-TIME:20070221T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0736@ictp.it
DESCRIPTION:A fundamental understanding of magnetic and spin-dependent phe
nomena requires the determination of spin structures and spin excitations
down to the atomic scale. The direct visualization of atomic-scale spin st
ructures [1-4] has first been accomplished for magnetic metals by combinin
g the atomic resolution capability of Scanning Tunnelling Microscopy (STM)
with spin sensitivity\, based on vacuum tunnelling of spin-polarized elec
trons [5]. The resulting technique\, Spin-Polarized Scanning Tunnelling Mi
croscopy (SP-STM)\, nowadays provides unprecedented insight into collinear
and non-collinear spin structures at surfaces of magnetic nanostructures
and has already led to the discovery of new types of magnetic order at the
nanoscale [6]. More recently\, the detection of spin-dependent exchange a
nd correlation forces has allowed a first direct real-space observation of
spin structures at surfaces of antiferromagnetic insulators [7]. This new
type of scanning probe microscopy\, called Magnetic Exchange Force Micros
copy (MExFM)\, provides a powerful new tool to investigate different types
of spin-spin interactions based on direct-\, super-\, or RKKY-type exchan
ge down to the atomic level. By combining SP-STM with inelastic electron t
unnelling spectroscopy or by performing MExFM together with high-precision
measurements of damping forces localized or confined spin excitations in
magnetic systems of reduced dimensions now become experimentally accessibl
e.\n\nReferences\n[1] R. Wiesendanger\, I. V. Shvets\, D. Bürgler\, G. Ta
rrach\, H.-J. Güntherodt\, J. M. D. Coey\, and S. Gräser\, Science 255\,
583 (1992)\; \n R. Wiesendanger\, I. V. Shvets\, D. Bürgler\, G. Tarrach
\, G. Güntherodt\, H.-J. Güntherodt\, and J. M. D. Coey\, Europhys. Lett
. 19\, 141 \n (1992)\n[2] S. Heinze\, M. Bode\, O. Pietzsch\, A. Kubetzka\
, X. Nie\, S. Blügel\, and R. Wiesendanger\, Science 288\, 1805 (2000)\n[
3] A. Kubetzka\, P. Ferriani\, M. Bode\, S. Heinze\, G. Bihlmayer\, K. vo
n Bergmann\, O. Pietzsch\, S. Blügel\, and R. Wiesendanger\, Phys. Rev. \
n Lett. 94\, 087204 (2005) \n[4] M. Bode\, E. Y. Vedmedenko\, K. von Bergm
ann\, A. Kubetzka\, P. Ferriani\, S. Heinze\, and R. Wiesendanger\, Natur
e Materials 5\, 477 (2006)\n[5] R. Wiesendanger\, H.-J. Güntherodt\, G. G
üntherordt\, R. J. Gambino\, and R. Ruf\, Phys. Rev. Lett. 65\, 247 (1990
)\n[6] K. von Bergmann\, S. Heinze\, M. Bode\, E. Y. Vedmedenko\, G. Bihl
mayer\, S. Blügel\, and R. Wiesendanger\, Phys. Rev. Lett. 96\, 167203
\n (2006)\n[7] U. Kaiser\, A. Schwarz\, and R. Wiesendanger\, Nature (2
007)\, in press\n\n//indico.ictp.it/event/a0736/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0736/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Electron fractionalization in one- and two-dimensional structures
DTSTART;VALUE=DATE-TIME:20070222T100000Z
DTEND;VALUE=DATE-TIME:20070222T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0737@ictp.it
DESCRIPTION://indico.ictp.it/event/a0737/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a0737/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club Seminar on Disorder and strong electron correlations:
"Electron fractionalization in one- and \ntwo-dimensional structures" - P
art II\n
DTSTART;VALUE=DATE-TIME:20070301T100000Z
DTEND;VALUE=DATE-TIME:20070301T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0745@ictp.it
DESCRIPTION://indico.ictp.it/event/a0745/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a0745/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Statistical Physics Seminar: "Off-critical statistical models in t
wo dimensions"\n
DTSTART;VALUE=DATE-TIME:20070306T113000Z
DTEND;VALUE=DATE-TIME:20070306T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0747@ictp.it
DESCRIPTION:This seminar intends to present the main theoretical ideas beh
ind the study of the statistical models in two dimensions\, such as unive
rsality\, integrability or breaking thereof. As example\, we will make a
thorough analysis of the class of universality of the Ising model: in par
ticular we focus on the universal ratios of the Renormalization Group and
on the spectrum of the excitations by varying the temperature or/and the m
agnetic field.\n\n//indico.ictp.it/event/a0747/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0747/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Multiphoton
processes in driven mesoscopic systems"\n
DTSTART;VALUE=DATE-TIME:20070308T100000Z
DTEND;VALUE=DATE-TIME:20070308T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0748@ictp.it
DESCRIPTION:In this seminar\, I will describe the dynamics in energy space
of a mesoscopic system\, specifically a quasi-1d ring threaded by an harm
onic time-dependent flux Phi(t)\, focusing on the the statistics of multi
-photon absorption/emission processes. For this sake\, I will demonstrate
a useful mapping of the dynamics of the electrons distribution function i
nto a Continuous Time Random Walk in energy space. Studying the probabilit
y to absorb/emit n quanta per scattering event\, we will explore the cr
ossover between ultra-quantum/low-intensity limit and quasi-classical/high
-intensity regime\, and the role of multiphoton processes in driving it.
Finally\, I will discuss the influence of quantum interference\, and the r
ole of system geometry in determining its effect.\n\n//indico.ictp.it/even
t/a0748/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a0748/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and Strong Electron Correlations: "The classic
al limit of quantum transport"
DTSTART;VALUE=DATE-TIME:20070313T123000Z
DTEND;VALUE=DATE-TIME:20070313T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0750@ictp.it
DESCRIPTION:The interference of multiply scattered quantum mechanical matt
er waves causes small but noticeable corrections to the conductance of a m
etal at low temperatures. Historically\, one separates the interference c
orrection to the electrical conductance into 'weak localization'\, a small
negative correction to the conductance averaged over an ensemble of condu
ctors with different impurity configurations\, and the 'conductance fluctu
ations'\, the sample-to-sample fluctuations measured with respect to the e
nsemble average. What is the fate of quantum interference corrections in
the limit that the wavelength of the electrons becomes small in comparison
to all other relevant length scales? This limit is a 'classical limit' s
imilar to the transition from wave optics to ray optics that occurs when t
he typical size of optical elements becomes much larger than the wavelengt
h of light. I'll show that\, whereas the interference correction to the e
nsemble-averaged conductance (weak localization) disappears in this classi
cal limit\, the quantum interference contribution to the sample-specific c
onductance fluctuations remains surprisingly unaffected.\n\n//indico.ictp.
it/event/a0750/
LOCATION:ICTP - Lecture Room 204 - II floor
URL://indico.ictp.it/event/a0750/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Modelling the evolu
tion of the influenza virus"\n
DTSTART;VALUE=DATE-TIME:20070314T113000Z
DTEND;VALUE=DATE-TIME:20070314T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0752@ictp.it
DESCRIPTION:The evolution of the virus of influenza A presents paradoxical
aspects: despite its rapid evolution to escape acquired immunity\, the vi
ral population remains concentrated with a behavior reminiscent of an evol
ving quasi-species. After an introduction to the ecology and the evolutio
n of Influenza\, I will discuss recent proposals to understand this behavi
our.\n\n//indico.ictp.it/event/a0752/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0752/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"Magnetic ph
ase diagram of the doped two-dimensional Kondo lattice model"\n
DTSTART;VALUE=DATE-TIME:20070315T100000Z
DTEND;VALUE=DATE-TIME:20070315T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0753@ictp.it
DESCRIPTION:The Kondo lattice model describes an array of magnetic impurit
ies embed in a metallic host and is believed to capture the physics of hea
vy fermion systems. Over the past years it has become possible to carry o
ut approximation free auxiliary field quantum Monte Carlo simulations of t
he KLM for the special case of a particle-hole symmetric conduction band.
Those results allow an understanding of the interplay between the RKKY i
nteraction and the Kondo effect which is at the origin of magnetic order-d
isorder quantum phase transitions in those models. In the ordered phase\,
the numerical results allow the interpretation of the coexistence\, rath
er than the mutual exclusion\, of magnetic ordering and Kondo screening.
The local moments are partially screened and the remnant moment orders mag
netically. The limitations of the above simulations lies in the requirem
ent of a particle-hole symmetric conduction band and invariably leads to i
nsulating ground states. To alleviate this restriction and to access meta
llic states\, approximate methods have to be used. We have opted for the
dynamical cluster approximation (DCA) with spin symmetry broken baths so
as to account for magnetically ordered states. In the special case of a
particle-hole symmetric conduction band the overall features of the DCA re
sults compare very favorably with exact auxiliary field simulations. Wit
hin the DCA\, the magnetically ordered phase survives finite doping and al
lows the study of the evolution of the single particle spectral function f
rom magnetic metallic states to paramagnetic heavy fermion states.\n\n//in
dico.ictp.it/event/a0753/
LOCATION:ICTP (Main Bldg. Lecture Room 204)
URL://indico.ictp.it/event/a0753/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: 'Statistical mechani
cs and financial markets'
DTSTART;VALUE=DATE-TIME:20070320T113000Z
DTEND;VALUE=DATE-TIME:20070320T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0757@ictp.it
DESCRIPTION:I will discuss shortly the empirical findings on financial mar
kets which have attracted the interest of statistical physicists\, the rel
evant interactions and the approaches which have been advanced to understa
nd them as critical phenomena. In particular\, I will concentrate on the c
ollective dynamics of the price of an ensemble of stocks\, review empirica
l studies and discuss a simple phenomenological model for the dynamics of
the center of mass (the so-called market mode)\, which accounts for the im
pact of optimal portfolio strategies.\n\n//indico.ictp.it/event/a0757/
LOCATION:SISSA - Lecture Room D
URL://indico.ictp.it/event/a0757/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Theory of 2
D superconductor with broken inversion symmetry"
DTSTART;VALUE=DATE-TIME:20070322T100000Z
DTEND;VALUE=DATE-TIME:20070322T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0758@ictp.it
DESCRIPTION:This seminar presents a theory of a phase diagram of a two-dim
ensional spin-orbital superconductor in a parallel magnetic field. A spin
-orbital interaction of the Rashba type is known to produce at a high magn
etic field (and in the absence of impurities) an inhomogeneous superconduc
tive phase similar to the Larkin-Ovchinnikov-Fulde-Ferrel (LOFF) state.
We consider the case of a strong Rashba interaction with the spin-orbital
splitting much larger than the superconductive gap\, and show that at low
temperatures the LOFF-type state is separated from the usual homogeneous s
tate by a first-order phase transition line. At higher temperatures anoth
er inhomogeneous state\, a new ``helical'' state\, intervenes between the
uniform BCS and the LOFF-like state. The superfluid density vanishes in
the region around the second-order transition line between the BCS and the
"helical'' state. Non-magnetic impurities suppress both inhomogeneous st
ates. However\, once an account is made of the next-order term over the s
mall ratio Rashba/Fermi velocity\, a relatively long-wave helical modulati
on develops from the BCS state. This long-wave modulation is stable with
respect to disorder. In addition\, we predict that unusual vortex defects
with a continuous core exist near the phase boundary between the helical a
nd the LOFF-like states. In particular\, in the LOFF-like state these def
ects may carry a half-integer flux.\n\n//indico.ictp.it/event/a0758/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a0758/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:"How can supe
rconductivity emerge out of a pseudo-gap metal: A novel scenario"
DTSTART;VALUE=DATE-TIME:20070329T100000Z
DTEND;VALUE=DATE-TIME:20070329T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0766@ictp.it
DESCRIPTION:Motivated by the physics of cuprates\, many attempts have been
recently done to understand how high temperature superconductivity may em
erge out of a pseudo-gap metal. The puzzle lies in the fact that one shou
ld naively expect that a pseudo-gap in the normal phase cuts off the singu
larity of the Cooper channel. Consequently a very strong pairing mechanis
m would be required to turn the pseudo-gap metal into a high temperature s
uperconductor. A similar scenario\, although in a different context from
cuprates\, was recently discovered\, in the framework of the so-called Str
ongly Correlated Superconductivity (SCS)\, solving by Dynamical Mean Field
Theory (DMFT) a two-orbital Hubbard model with a Jahn-Teller pairing mech
anism. The DMFT phase diagram has revealed a very rich phenomenology wher
e a superconductor with an huge gap and a large Drude weight comes out of
a pseudo-gapped Non Fermi Liquid phase just close to a singlet Mott insula
tor. To get a further insight into such an appealing scenario\, we presen
t in this talk a simple analytical ansatz for the low-energy part of the s
elf-energy in this model. Our approach mainly relies on the physical idea
that symmetry breaking provides the system with a low-energy scale\, iden
tified with the superconducting gap\, that regularizes all non-Fermi-liqui
d singularities of the normal phase\, thus restoring well-defined quasipar
ticles within the superconducting phase. Within this scenario\, supercond
uctivity seems to be the natural fate of the pseudo-gap metal at low tempe
rature\, rather then a competitor. To check the ansatz we compare our mod
el self-energy with data coming from DMFT as well as from a closely relate
d impurity model. While the former only partially confirm our approach\,
mainly due to the limited energy resolution of DMFT data\, the latter stro
ngly support our scenario.\n\n//indico.ictp.it/event/a0766/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a0766/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on disorder and strong electron correlations: "Caustics\,
focusing and Veselago lens in P-N junctions in graphene"\n
DTSTART;VALUE=DATE-TIME:20070402T100000Z
DTEND;VALUE=DATE-TIME:20070402T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0772@ictp.it
DESCRIPTION:There are many similarities between optics and electronics: Ra
ys in geometrical optics are analogous to classical trajectories of electr
ons\, while electron de Broglie waves can interfere. The electron microsc
ope is one example of the technological implementation of this similarity.
The analogy with optics may also hold a significant potential for semico
nductor electronics. In optics\, transparent interfaces between materials
are used in lenses and prisms to manipulate light beams. From this persp
ective\, an unusual promise is offered by the recently discovered two-dime
nsional gapless semiconductor\, graphene. Fine-tuning of the carrier dens
ity in graphene by means of electrical gates or doping of the underlying s
ubstrate was demonstrated\, thus\, paving the way towards controllable bal
listic PNJs. On the one hand\, the PNJ in graphene is highly transparent
for the charge carriers. On the other\, the transmission of electrons thr
ough the p-n interface may resemble optical refraction at the surface of m
etamaterials with negative refractive index: the straight interface is abl
e to focus electric current whereas a ballistic stripe of p-type graphene
separating two n-type regions acts as a lens. In this talk\, I shall revi
ew the properties of graphene and p-n junctions in this material leading t
o the focusing effect\, discuss form of cautics replacing the focus in asy
mmetric p-n junctions\, and describe the proposal of Veselago lens and foc
using prism/beam splitter in graphene.\n\nReferences:\nV. Cheianov\, V.I.
Fal’ko\, B.L. Altshuler - Science 315\, 1252 (2007)\nV. Cheianov and V.I
. Fal’ko - Phys. Rev. B 74\, 041403 (2006)\n\n//indico.ictp.it/event/a07
72/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a0772/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"Ellipse of
constant entropy in the XY spin chain"
DTSTART;VALUE=DATE-TIME:20070412T100000Z
DTEND;VALUE=DATE-TIME:20070412T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0774@ictp.it
DESCRIPTION:We study the bi-partite entanglement in the ground state of th
e one-dimensional XY spin 1/2 model\, by calculating the Von Neumann Entro
py of a block of neighboring spins. We consider the double-scaling limit
in which the block size is much bigger than unity\, but still much smaller
than the length of the whole chain. As long as the system is gapped\, as
the size of the block increases toward infinity\, the entropy reaches a f
inite saturation value. We study this limit entropy in the two-dimensional
phase diagram of the system\, as a function of the anisotropy parameter a
nd of the external magnetic field. We identify its minima at product stat
es and its divergences at the quantum phase transitions. We find that the
curves of constant entropy are ellipses and hyperbolae and that they all m
eet at one point (it essential critical point). The entropy is highly dis
continuous across this point: depending on the direction of approach to th
e essential critical point the entropy can take any value on the positive
real axis. In the vicinity of this point small changes in the parameters
cause drastic changes of the entropy and this can be really important for
quantum control. Finally\, I will present some more technical results fro
m a work in progress\, in which a second\, degenerate\, ground state of th
e model is identified and I'll briefly discuss its meaning and significanc
e.\n\n//indico.ictp.it/event/a0774/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a0774/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on disorder and strong electron correlations: "Decohering
quantum transport: Phase reservoir"\n
DTSTART;VALUE=DATE-TIME:20070419T100000Z
DTEND;VALUE=DATE-TIME:20070419T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0782@ictp.it
DESCRIPTION:A phenomenology of random-phase reservoir will be introduced a
nd examined in the context of the reservoir-induced decoherence of quantum
transport in the presence of static disorder.\n\n//indico.ictp.it/event/a
0782/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a0782/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA statistical physics seminar: "Nonlinear magnetotr
ansport in chiral interacting nanotubes "\n
DTSTART;VALUE=DATE-TIME:20070424T113000Z
DTEND;VALUE=DATE-TIME:20070424T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0781@ictp.it
DESCRIPTION:Nonlinear transport through interacting single-wall carbon nan
otubes containing a few impurities is studied theoretically. Extending th
e Luttinger liquid theory to incorporate trigonal warping and chirality ef
fects\, we derive the current contribution odd in an orbital magnetic fiel
d B\, which is non-zero only for chiral tubes and is a direct manifestatio
n of interaction physics.\n\n//indico.ictp.it/event/a0781/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0781/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n" Interferen
ce and correlations in \ntwo-level transport through quantum dots"\n
DTSTART;VALUE=DATE-TIME:20070503T100000Z
DTEND;VALUE=DATE-TIME:20070503T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0793@ictp.it
DESCRIPTION:Two-level quantum dots coupled to two reservoirs with spinless
electrons with no particular symmetries can be mapped exactly to a genera
lized spinful single-impurity Anderson model. We give a general character
ization of charge occupation numbers and linear conductance in regime inte
rlevel Coulomb repulsion by employing various analytical techniques develo
ped for the local moment regime of the Anderson model. Implications for p
opulation inversion\, transmission phase lapse and orbital Kondo effect in
quantum dots are discussed.\n\n//indico.ictp.it/event/a0793/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a0793/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Folding of small pr
oteins in explicit solvent by the combined use of metadynamics and replica
exchange"
DTSTART;VALUE=DATE-TIME:20070508T113000Z
DTEND;VALUE=DATE-TIME:20070508T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0795@ictp.it
DESCRIPTION:We recently developed a method that combines replica exchange
with metadynamics and allows\, with a moderate computational effort\, the
simultaneous reconstruction of the free energy as a function of a large nu
mber of variables. This allows simulating very complex reactions\, like p
rotein folding\, in which the reaction coordinate is totally unknown. We
will discuss applications of the methodology to the folding in explicit so
lvent of the TRP cage miniprotein and of the advillin headpiece C-terminal
domain (cHP) and its Pro62Ala mutant. Our calculations allow\, for these
small proteins\, the ab initio prediction of the folded state. For the a
dvillin headpiece we find that the Pro62Ala mutation does not change the o
verall stability of the native state but it significantly alters the entro
pic contribution to the folding free energy. Therefore\, the mutant is st
ill folded at room temperature but is characterized by a lower unfolding t
emperature. This prediction was subsequently validated by NMR and CD exper
iments.\n\n//indico.ictp.it/event/a0795/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0795/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:\n"Real time
evolution of quantum many-particle systems: The flow equation approach"
DTSTART;VALUE=DATE-TIME:20070510T100000Z
DTEND;VALUE=DATE-TIME:20070510T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0798@ictp.it
DESCRIPTION:The analytical evaluation of the real time evolution of a quan
tum many-particle system far out of equilibrium poses a challenging proble
m. Without prior knowledge about the long-time behavior\, perturbative ca
lculations suffer from spurious terms (secular terms)\, which grow in an
uncontrolled way for large times. The flow equation approach (infinitesim
al unitary transformation approach) can overcome some of these problems by
studying the real time evolution of observables in the Heisenberg picture
in a suitable energy-diagonal basis. This basis is obtained by an approx
imate renormalization group- like diagonalization of the Hamiltonian. In t
his talk I will review the method and show its application to various quan
tum many-particle problems.\n\n//indico.ictp.it/event/a0798/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a0798/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Thermostats\, entro
py and chaotic hypothesis"\n
DTSTART;VALUE=DATE-TIME:20070515T113000Z
DTEND;VALUE=DATE-TIME:20070515T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07103@ictp.it
DESCRIPTION:A review of recent results\, theoretical\, numerical and exper
imental on attempts to a general theory of nonequilibrium statistical mech
anics. Large fluctuations and fluctuation theorem.\n\n//indico.ictp.it/eve
nt/a07103/
LOCATION:SISSA Main Bldg. - Lecture Room 'D'
URL://indico.ictp.it/event/a07103/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: 'Boundary field theo
ry approach to Josephson devices'
DTSTART;VALUE=DATE-TIME:20070522T113000Z
DTEND;VALUE=DATE-TIME:20070522T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07107@ictp.it
DESCRIPTION:I show that some superconducting Josephson devices may be rega
rded as a condensed matter realization of a two boundary sine Gordon model
. Using boundary field theory methods I will compute both the DC Josephso
n current and the normal component of the current-response of SQUIDs to an
externally applied voltage. The approach helps in establishing new and s
omewhat unexpected connections between superconducting devices and quantum
impurity problems.\n\n//indico.ictp.it/event/a07107/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07107/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter seminar: "DNA interaction\, reco
gnition and aggregation. Love at first sight"
DTSTART;VALUE=DATE-TIME:20070523T150000Z
DTEND;VALUE=DATE-TIME:20070523T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07114@ictp.it
DESCRIPTION:How can meters of genetic material be packed in mammalian sper
m and phage heads? Why do some ions condense DNA\, while others do not?
Why does DNA change its structure in dense aggregates? These and other qu
estions\, including a mechanism for snap-shot genegene recognition in reco
mbination of homologous genes suggested by Kornyshev and Leikin are addres
sed within an ongoing research program of a ‘transatlantic’ team at th
e Departments of Chemistry and Molecular Biosciences of Imperial College L
ondon\, and the Physical Biochemistry Group of the Institute of Child Heal
th and Human Development of the National Institute of Health (Bethesda\, M
D\, USA). This project is based on Kornyshev-Leikin theory of interaction
of helical macromolecules in solutions. In line with a wealth of experime
ntal data (such as the observed poly- and meso-morphism of DNA assemblies\
, and the measured decay range of repulsive forces between various helical
macromolecules) this theory was recently extended to the statistical mech
anics of DNA columnar and cholesteric phases\, and DNA mechanics - mapped
on forefront models of nonlinear physics (A. Cherstvy\, A. Kornyshev\, D.J
. Lee\, S. Leikin\, A. Wynveen). One of the recent results was the experi
mental proof of azimuthal correlations between DNA in hydrated aggregates
(A.A. Kornyshev\, D.J. Lee\, S. Leikin\, A. Wynveen\, S. Zimmerman)\, pred
icted by the theory. The latest experiments of Imperial-NIH team (G. Baldw
in\, N. Brooks\, A. Goldar\, S. Leikin\, R. Robson\, J. Seddon) has recent
ly approved existence of the physical mechanism of homology recognition in
protein free environment\, predicted by KL in 2001. The effect of homolog
y recognition is what presumably warrants against errors in homologous rec
ombination of genes – the process responsible for evolution and genetic
diversity\, as well DNA repair. Thus understanding the recognition mechani
sm may result in the future in understanding how to avoid such errors that
themselves are responsible for a number of genetically determined disease
s\, such as cancer and Atzheimer’s on one hand\, or aging on the other h
and.\nThis talk will introduce the audience to the principles of the theor
y\, present some of its main results\, and review the latest experimental
findings. An interested listener is referred to a detailed article which
will be published in the June issue of Reviews of Modern Physics: A.A. Kor
nyshev\, D.J. Lee\, S. Leikin\, and A. Wynveen: Structure and interactions
of biological helices\, and the original publications\, listed below.\n\n
\nTheory of interaction between helical molecules\nA.A.Kornyshev and S.Lei
kin\, J.Chem.Phys. 1997\,107\, 3656.\n\nSymmetry laws for interaction betw
een helical macromolecules.\nA.A.Kornyshev and S.Leikin\, Biophys.J.\, 199
8\, 75\, 2513.\n\nHelical symmetry and electrostatic interaction of macrom
olecules in dense aggregates. An impetus for DNA poly- and meso-morphism.\
nA.A.Kornyshev and S.Leikin\, Proc.Natl.Acad.Sci.USA. 1998\, 95\, 13579.\n
\nElectrostatic zipper motif for DNA aggregation.\nA.A.Kornyshev and S.Lei
kin\, Phys.Rev.Lett.\, 1999\, 82\, 4138.\n\nA twist in chiral interaction
between biological helices.\nA.A.Kornyshev and S.Leikin\, Phys.Rev.Lett. 2
000\, 84\, 2537.\n\nElectrostatic interaction between long\, rigid helical
macromolecules at all interaxial angles\nA.A.Kornyshev and S.Leikin\, Phy
s.Rev.E\, 2000\, 62\, 2576.\n\nSequence recognition in pairing of DNA dupl
exes.\nA.A.Kornyshev and S.Leikin\, Phys.Rev.Lett. 2001\, 86\, 3666. DNA n
eed not unzip.-\nhttp://focus.aps.org/v7/st19.html\n\nChiral electrostatic
interactions and cholesteric liquid crystals of DNA.\nA.A.Kornyshev\, S.L
eikin\, and S.Malinin\, European Phys.J. E (Soft Matter) 2002\, 7\, 83.\n\
nPhase behavior of columnar DNA assemblies.\nH.M.Harreis\, A.A.Kornyshev\,
C.N.Likos\, H.Loewen\, and G.Sutmann\, Phys.Rev.Lett. 2002\, 89\, art.#18
303.\n\nTemperature-dependent DNA condensation triggered by rearrangement
of adsorbed cations.\nA.G. Cherstvy\, A.A.Kornyshev\, S.Leikin\, J.Phys.Ch
em.2002\,106\, 13362.\n\nTorsional Deformation of Double Helix in Interact
ion and aggregation of DNA.\nA.G.Cherstvy\, A.A.Kornyshev\, and S.Leikin\,
J.Phys.Chem.B\, 2004\, 108\, 6508.\n\nNonlinear effects in torsional adju
stment of interacting DNA.\nA.Kornyshev and A.Wynveen\,. Phys.Rev.E\, 2004
\, 69\, #041905\, 1-14.\n\nDNA-DNA interaction beyond the ground state.\nD
.J.Lee\, A.Wynveen\, and A.A.Kornyshev\, Phys. Rev. E\, 2004\, 70\, #05191
3\, 1-12\n\nStatistical mechanics of DNA assemblies.\nA.Wynveen\, D.J.Lee\
, and A.A.Kornyshev\, Eur.Phys.J. E\, 2005\, 16\, 303.\n\nTorsional fluctu
ations in columnar DNA assemblies.\nD.J.Lee and A.Wynveen\, J.Phys: Conden
sed Matter\, 18\, 786 (2006).\n\nDNA melting in aggregates: impeded or fac
ilitated?\nA.G.Cherstvy and A.A.Kornyshev\, J.Phys.Chem.B\, 2004\, 108\, 6
508.\n\nDirect observation of azimuthal correlations between DNA in hydrat
ed aggregates\nA.A.Kornyshev\, D.J.Lee\, S.Leikin\, A.Wynveen\, S.Zimmerma
n\, Phys.Rev.Lett. 2005\, 95\,#148102.\n\n//indico.ictp.it/event/a07114/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07114/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Mesoscopic
to universal crossover of transmission phase of multi-level quantum dots"\
n
DTSTART;VALUE=DATE-TIME:20070524T150000Z
DTEND;VALUE=DATE-TIME:20070524T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07108@ictp.it
DESCRIPTION:Transmission phase measurements of many-electron quantum dots
(small mean level spacing \\delta) revealed universal phase lapses by \\p
i between consecutive resonances. In contrast\, for dots with only a few
electrons (large \\delta) the appearance or not of a phase lapse depends o
n the dot parameters. We show that a model of a multi-level quantum dot w
ith local Coulomb correlations and arbitrary level-lead couplings reproduc
es the generic features of the observed behavior. The universal behavior
at small follows from Fano-type antiresonances of pairs of renormalized si
ngle-particle levels.\n\n//indico.ictp.it/event/a07108/
LOCATION:ICTP Main Building Lecture Room D
URL://indico.ictp.it/event/a07108/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "New develo
pments in quantum chaos"\n
DTSTART;VALUE=DATE-TIME:20070529T150000Z
DTEND;VALUE=DATE-TIME:20070529T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07116@ictp.it
DESCRIPTION:The last few years have witnessed drastic advances in the fiel
d of quantum chaos: building on a fundamentally new understanding of quant
um interference\, novel analytic approaches to quantitatively describe mes
oscopic phenomena in chaotic systems (similar in nature to the impurity di
agram techniques of disordered systems) have been developed. These new th
eoretical potentials have made it possible to finally explain the basis of
universality - i.e. the phenomenon that the spectra of individual chaotic
systems behave according to the phenomenological predictions of random ma
trix theory. They have also been applied to successfully address a spectr
um of mesoscopic fluctuation phenomena\, both in thermodynamics and trans
port. All in all\, the theory of mesoscopic fluctuations in /individual /
chaotic systems finally seems to have leveled with the previously much hig
her developed theory of disordered electronic systems. In this talk I wil
l give an overview of the most important recent developments. Some emphasi
s will be put on elucidating parallels between the different approaches to
the problem\, notably between periodic orbit theory and quantum field the
ory.\n\n//indico.ictp.it/event/a07116/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a07116/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:\n"Luttinger
liquids with curvature: Density correlations and Coulomb drag effect"\n
DTSTART;VALUE=DATE-TIME:20070531T100000Z
DTEND;VALUE=DATE-TIME:20070531T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07118@ictp.it
DESCRIPTION:I discuss the effect of the curvature in fermionic dispersion
on the observable properties of Luttinger liquid (LL). In the bosonizatio
n technique the curvature is irrelevant perturbation\, describing the dec
ay of LL bosons (plasmon modes). When possible\, I show the correspondenc
e between the bosonization and the fermionic approach. The most important
application of this approach is the analysis of the Coulomb drag by small
momentum transfer between two LL\, which is only possible due to curvatur
e. Analyzing the a.c. transconductivity in the one-dimensional drag setup
\, I confirm the results by Pustilnik {\\em et al.} for $T-$dependence of
drag resistivity\, $R_{12} \\sim T^2$ at high and $R_{12} \\sim T^5$ at
low temperatures. The bosonization allows for treating both intra- and in
ter-wire electron-electron interactions in all orders\, and I calculate th
e exact prefactors in low-T drag regime. The crossover temperature betwee
n the two regimes is $T_1 \\sim E_F \\Delta$\, with $\\Delta$ relative dif
ference in plasmon velocities. I show that $\\Delta \\neq 0$ even for iden
tical wires\, due to lifting of plasmon degeneracy by interwire interactio
n\, $U_{12}$\, leading to crossover from $R_{12} \\sim U_{12}^2 T^2$ to $R
_{12} \\sim T^5/U_{12}$ at $T \\sim\n\n//indico.ictp.it/event/a07118/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07118/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Entanglement genera
tion by a noisy environment"\n
DTSTART;VALUE=DATE-TIME:20070605T113000Z
DTEND;VALUE=DATE-TIME:20070605T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07121@ictp.it
DESCRIPTION:We shall discuss bipartite entanglement generation of purely d
issipative origin in open systems immersed in a common environment. The s
hort and long time entangling power of the environment will be examined to
gether with its control through phenomenological parameters.\n\n//indico.i
ctp.it/event/a07121/
LOCATION:SISSA - Lecture Room 'D'
URL://indico.ictp.it/event/a07121/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Quantized turbulenc
e"
DTSTART;VALUE=DATE-TIME:20070612T113000Z
DTEND;VALUE=DATE-TIME:20070612T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07129@ictp.it
DESCRIPTION:We discuss recent results on visualizing quantized vortices us
ing tiny particles of solid hydrogen and discuss phenomena such as vortex
reconnection.\n\n//indico.ictp.it/event/a07129/
LOCATION:SISSA Main Bldg - Lecture Room 'D'
URL://indico.ictp.it/event/a07129/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar: "What is new in the rea
lm of quantum electronic transport in mesoscopic physics?"
DTSTART;VALUE=DATE-TIME:20070613T150000Z
DTEND;VALUE=DATE-TIME:20070613T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07128@ictp.it
DESCRIPTION:The prime signature of transport in quantum wires and quantum
point contacts\, namely the quantisation of conductance into 'Landauer ste
ps' in units of 2e^2/h\, appears to be adequately explained in terms of co
herent transmission of electron waves through a loss free barrier. Howeve
r\, the picture of quantum coherent scattering at this phenomenological le
vel can not address the central issue of metallic conduction: what causes
dissipation in a ballistic quasi-one dimensional wire. \nIn this talk I s
hall present answer to this vexed question by many-body quantum kinetics\,
totally free of unwanted phenomenologies. Our microscopic application of
well-tested many-body methods leads not only to conductance quantisation
by precise accounting for inelastic energy loss\, but we also resolve a l
ong standing experimental enigma in the fluctuation spectra of a quantum p
oint contact. I shall also highlight some recent controversy regarding ne
gative resistance in three- and four-terminal devices.\nThe talk will be p
resented at a pedagogic level.\n\n//indico.ictp.it/event/a07128/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07128/
END:VEVENT
BEGIN:VEVENT
SUMMARY:CONDENSED MATTER SECTION-INFORMAL SEMINAR:"Anomalous c-axis transp
ort in layered metals" \n
DTSTART;VALUE=DATE-TIME:20070615T100000Z
DTEND;VALUE=DATE-TIME:20070615T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07132@ictp.it
DESCRIPTION:Transport in many layered materials (cuprates\, perovskites\,g
raphite\, etc.) shows an interesting anomaly: whereas the temperature depe
ndence of the in-plane resistivity is metallic\, that of the out-of-plane
(c-axis) resistivity is insulating or even non-monotonic. We show that the
band transport in all directions\, described by the standard Boltzmann eq
uation\, is robust with respect to both elastic and inelastic scattering a
s long as E_F\\tau>>1. A model of phonon-assisted tunneling via resonant s
tates located in between the layers is suggested to explain a non-monotoni
c temperature dependence of the c-axis resistivity observed in experiments
.\n\n//indico.ictp.it/event/a07132/
LOCATION:ICTP-Main Building-Seminar Room
URL://indico.ictp.it/event/a07132/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA CONDENSED MATTER SEMINAR:"Cultural hitchhiking on
the wave of advance of beneficial technologies"
DTSTART;VALUE=DATE-TIME:20070620T150000Z
DTEND;VALUE=DATE-TIME:20070620T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07133@ictp.it
DESCRIPTION:The wave-of-advance model was introduced to describe the sprea
d of advantageous genes in a population. It can be adapted to model the up
take of any advantageous technology through a population\, such as the arr
ival of neolithic farmers in Europe\, the domestication of the horse\, the
wheel\, iron tools\, political organisation or advanced weaponry. Any tra
it which preexists alongside the advantageous one could be carried along w
ith it\, such as genetics or language\, regardless of any intrinsic superi
ority. Decoupling of the advantageous trait from other “hitchhiking” t
raits depends on its adoption by the preexisting population. I shall descr
ibe work done by Ackland\, Signitzer\, Stratford and myself in which we co
nstructed a wave-of-advance model for agriculture based on food production
on a heterogeneous landscape with interaction of multiple populations. T
wo key results arise from geographic inhomogeneity: the “subsistence bou
ndary” at land so poor that the wave of advance is halted\, and the temp
orary “diffusion boundary” where the wave cannot move into poorer area
s until its gradient becomes sufficiently large. At diffusion boundaries\,
farming technology may pass to indigenous people already in those poorer
lands\, allowing their population to grow and resist encroachment by farme
rs. Ultimately\, this leads to the halt in spread of the “hitchhiking”
trait and establishment of a permanent “cultural boundary” between di
stinct cultures with equivalent technology. These phenomena are illustrat
ed by simulations of the transition between hunting and gathering and neol
ithic agriculture in Europe and in the Indian subcontinent and by the adva
nce of European agriculture into Southern Africa much later. Physical con
cepts underlie the construction of the model--diffusion\, mobility\, and a
n Einstein relation between them\; nonlinear wave propagation in an inhomo
geneous medium\; relaxation processes. The work provides an example of th
e power of physical reasoning in an interdisciplinary context.\n\n//indico
.ictp.it/event/a07133/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07133/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Condensed Matter Physics Associates’ Meeting: "Effective Mean-Fi
eld Theory for Heisenberg Zigzag Ladder"
DTSTART;VALUE=DATE-TIME:20070621T150000Z
DTEND;VALUE=DATE-TIME:20070621T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07135@ictp.it
DESCRIPTION://indico.ictp.it/event/a07135/
LOCATION:ICTP-Lecture room D-MB-Terrace level
URL://indico.ictp.it/event/a07135/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Finite size-effects
of the supersymmetric Sine-Gordon model with Dirichlet boundary condition
s"\n
DTSTART;VALUE=DATE-TIME:20070626T113000Z
DTEND;VALUE=DATE-TIME:20070626T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07199@ictp.it
DESCRIPTION:Starting from the Bethe Ansatz solution of the open integrable
spin-1 XXZ quantum spin chain with diagonal boundary terms\, we derive a
set of nonlinear integral equations (NLIEs)\, which we propose to describe
the boundary supersymmetric sine- Gordon model BSSG+ with Dirichlet bound
ary conditions on a finite interval. We compute the corresponding boundary
S matrix. We also derive a relation between the (UV) parameters in the bo
undary conditions and the (IR) parameters in the boundary S matrix. By com
puting the boundary vacuum energy\, we determine a previously unknown para
meter in the scattering theory. We solve the NLIEs numerically for interme
diate values of the interval length\, and find agreement with our analytic
al result for the effective central charge in the UV limit and with bounda
ry conformal perturbation theory.\n\n//indico.ictp.it/event/a07199/
LOCATION:Lecture Room 'D'-SISSA Main Building
URL://indico.ictp.it/event/a07199/
END:VEVENT
BEGIN:VEVENT
SUMMARY:INFORMAL SEMINAR on Statistical Physics: " Evolutionary constrai
nts in metabolic and genetic networks "
DTSTART;VALUE=DATE-TIME:20070628T150000Z
DTEND;VALUE=DATE-TIME:20070628T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07203@ictp.it
DESCRIPTION:Cellular metabolism consists of a complex network of chemical
reactions\, which transform hundreds of small molecules into each other in
order to secure a reliable supply of energy and building blocks. Understa
nding how cells manage their resources and network flows under different e
nvironmental conditions is a key question in systems biology. In addition
to being relevant for practical applications\, such as the identification
of key genes involved in metabolic diseases\, or the design of bioprocesse
s for optimal production of biofuels\, this question is tightly related to
the broader problem of how biological networks evolve through natural sel
ection. By implementing steady state models of genome-scale metabolic netw
orks and studying the response to single and double gene deletions in micr
obial cells\, we formulate new hypotheses about the capacity of cells to r
each optimal states\, and uncover a global organization of genes and pathw
ays into hierarchical modules associated with different biological functio
ns.\n\n//indico.ictp.it/event/a07203/
LOCATION:ICTP Main Building Lecture Room D
URL://indico.ictp.it/event/a07203/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Condensed Matter Physics Associates’ Meeting:" An exact solvable
model exhibiting negative specific heat "\n\n
DTSTART;VALUE=DATE-TIME:20070712T150000Z
DTEND;VALUE=DATE-TIME:20070712T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07213@ictp.it
DESCRIPTION:The successful observation of negative specific in nanocluster
s triggers hot theoretical explorations as to how applying statistical mec
hanics to finite-sized systems. In this talk\, we will use a simple model\
, free particles in the well\, to show the existence the negative heat cap
acity for a system with a finite number of particles.\n\n//indico.ictp.it/
event/a07213/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a07213/
END:VEVENT
BEGIN:VEVENT
SUMMARY:INFORMAL SEMINAR on Statistical Physics: " Orientational orderin
g of hard long rods on a lattice "\n\n
DTSTART;VALUE=DATE-TIME:20070718T100000Z
DTEND;VALUE=DATE-TIME:20070718T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07214@ictp.it
DESCRIPTION:The study of systems hard rods has a long history. In 1949\, O
nsager argued that a system of hard rod-like molecules in solution with on
ly excluded volume interaction would show long-range orientational order f
or high solvent densities. The existence of an orientationally ordered pha
se in the case of lattice models of straight hard rods of length k has rem
ained controversial so far. Only the case k=2 is analytically soluble. \nW
e argue that a system of straight rigid rods of length k on square lattice
with only hard-core interactions shows two phase transitions as a functio
n of density ρ for k ≥ 7. There is a phase transition from the low-dens
ity disordered phase to a nematic phase as ρ is increased from 0 at ρ =
ρc1\, and there is a second phase transition from the nematic phase to a
disordered phase at ρ = ρc2 \n\n//indico.ictp.it/event/a07214/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07214/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Seminar: "New paradigm for spin response in a two
-dimensional electron liquid with Rashba spin-orbit coupling" \n
DTSTART;VALUE=DATE-TIME:20070718T150000Z
DTEND;VALUE=DATE-TIME:20070718T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07218@ictp.it
DESCRIPTION://indico.ictp.it/event/a07218/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07218/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Condensed Matter Seminar: "Bound states and phase separat
ion \nin a t-J model"\n
DTSTART;VALUE=DATE-TIME:20070719T100000Z
DTEND;VALUE=DATE-TIME:20070719T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07217@ictp.it
DESCRIPTION:In this talk I shall present the low density phase diagram for
a t - J model on two dimensional square and honeycomb lattices. The phas
e diagram as a function of the exchange interaction\, J\, in both systems
possesses three distinct phases\, viz. a gas of free electrons\, (ii) a ga
s of pairs and finally (iii) a fully phase separated state. Further\, it
is rigorously proven that the phase boundary for the first phase (gas of e
lectrons) remains same in both the lattice geometries considered here (mor
e generally it is shown to be true for all bipartite lattices and is indep
endent of dimensionality of the system)\, while for the latter phases\, th
e boundaries are somewhat different. Moreover\, the existence of bigger cl
usters (bound states of three and four electrons etc.) are carefully inves
tigated using exact diagonalization (ED) and variational studies and possi
bility for them to occur in the phase diagram is ruled out. Implications
of such studies to superconductivity are discussed.\n\n//indico.ictp.it/ev
ent/a07217/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a07217/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Condensed Matter Physics Associates' Meeting: " Variational approa
ch to hydrodynamics of superfluid systems "
DTSTART;VALUE=DATE-TIME:20070719T150000Z
DTEND;VALUE=DATE-TIME:20070719T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07219@ictp.it
DESCRIPTION:We study the variational approach to hydrodynamics of superflu
id systems. We construct an effective Lagrangian describing the non-dissi
pative hydrodynamics of a more general system that is a supersolid phase.
The Hamilton equations of motion are obtained from the principle of stati
onary action. The closed algebra of Poisson brackets is also found. The
Hamilton equations of motion in the leading approximation with respect to
spatial gradients of local thermodynamic variables result in hydrodynamic
equations. It is shown that hydrodynamic equations coincide with the supe
rsolid Andreev-Livshitz hydrodynamics (non-dissipative) if to impose the c
onstraint on thermodynamic potential associated with Galilean invariance.
An effective Lagrangian also describes the ordinary superfluid hydrodynam
ics.\n\n//indico.ictp.it/event/a07219/
LOCATION:ICTP - Main Bldg. Lecture Rrom 'B'
URL://indico.ictp.it/event/a07219/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar: " Theory of supersolid
phenomena "
DTSTART;VALUE=DATE-TIME:20070725T150000Z
DTEND;VALUE=DATE-TIME:20070725T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07222@ictp.it
DESCRIPTION:Quantum fluctuations in Solid He 4 leads to a variety of inter
esting phenomena. One such possibility is a supersolid phase\, where a fr
agile superfluidity survives in the crystalline state. Recent experimental
observations of non classical moment of inertia by Kim and Chan claim to
confirm this exotic phase. After giving a background I will review my rec
ent theory [1] of the supersolid phenomena. In my theory\, quantized vort
ices play a fundamental role. Quantized vortices in He4 have a very small
core energy and core size (about 1 Au). Quantized vortex loops are also pr
esent in the superfluid\, as quantum fluctuations. Pressure beyond 25 atmo
sphere generates a spontaneous vortex-antivortex lattice\, also self consi
stently develops an atom density wave with hcp symmetry. Supersolid He4 i
s a vortex solid. Many of the existing phenomenology gets explained and s
ome interesting predictions are made.\n\n[1] And quiet flows the supersoli
d\, G. Baskaran\, cond-mat/0505160\n\n//indico.ictp.it/event/a07222/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07222/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Condensed Matter Physics Associates' Meeting: "Metal-insulator tra
nsition and maximum in magnetic susceptibility in 2D electron gas "\n
DTSTART;VALUE=DATE-TIME:20070726T150000Z
DTEND;VALUE=DATE-TIME:20070726T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07221@ictp.it
DESCRIPTION:In this talk we will discuss the experimental observations on
the metal-insulator transition (MIT) in the 2D electron gas (2DEG) and th
e thermodynamic measurements of the magnetic susceptibility and inverse co
mpressibility of this system. Next\, our model based on density function
al theory will be introduced\, in which disorder and interactions are trea
ted on the same footing without any assumption on their relative strength.
Obtained results on thermodynamic quantities and their relationship wit
h the MIT will be discussed based on our ensemble averaged DFT-based calcu
lations on this system.\n\n//indico.ictp.it/event/a07221/
LOCATION:ICTP - Lecture Room B
URL://indico.ictp.it/event/a07221/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Condensed Matter Section Informal Seminar: "Quantum critical regio
n of the disorder-driven superconductor-insulator transition"
DTSTART;VALUE=DATE-TIME:20070726T100000Z
DTEND;VALUE=DATE-TIME:20070726T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07223@ictp.it
DESCRIPTION:I present results of the experimental study of the low-tempera
ture transport properties of disordered thin TiN superconducting films acr
oss the localization threshold. The films exhibit an extremely sharp sepa
ration between the well-defined superconducting- and insulating phases\, d
emonstrating thus unambiguously the direct disorder-driven superconductor-
insulator transition. Although the films choose unequivocally between the
either superconducting or insulating ground states\, the temperature- and
magnetic-field behaviors of the resistance reveal an insulating trend in
the superconducting films and a superconducting trend in the insulating fi
lms. At zero and low magnetic fields the conductivity of insulating films
is thermally activated\, with the activation energy being nonmonotonic an
d magnetic-field dependent. In all samples\, including insulating films\,
magnetoresistance varies non-monotonously with the magnetic field\, start
ing with the positive magnetoresistance at low fields\, then reaching the
maximum\, followed first by the rapid drop and the eventual saturation at
higher magnetic fields. At these high fields the difference between the i
nsulating and superconducting samples vanishes and all curves converge to
the resistance close to the quantum value. At very low temperatures a sha
rp depinning voltage threshold in conductivity is observed. Our results a
nd the comparison with other studies on InOx clearly indicate that\, in th
e vicinity of the disorder-driven superconductor-insulator transition\, th
e response to the applied magnetic and/or electric fields\, is the same ir
respectively to whether the underlying ground state is superconducting or
insulating. The observed similarity allows for conjecture that in the cr
itical region of the transition a peculiar highly inhomogeneous "supercond
ucting insulator" forms. This inhomogeneity may be considered as self-ind
uced granularity\, coming from the strong mesoscopic fluctuations in disor
dered thin superconducting films and/or the fractal character of the elect
ronic wave functions near the localization threshold.\n\n//indico.ictp.it/
event/a07223/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a07223/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Statistical Physics: "Fluctuations\, pauses an
d backtracking in DNA transcription "\n
DTSTART;VALUE=DATE-TIME:20070820T160000Z
DTEND;VALUE=DATE-TIME:20070820T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07230@ictp.it
DESCRIPTION:Transcription is a vital stage in the process of gene expressi
on and a major contributor to fluctuations in gene expression levels for w
hich it is typically modelled as a single step process with Poisson statis
tics. However\, recent single molecule experiments raise questions about
the validity of such a simple single step picture. We present a molecular
multi-step model of transcription elongation that demonstrates that trans
cription times are in general non-Poisson distributed. In particular\, we
model transcriptional pauses due to backtracking of the RNA polymerase as
a first passage process. By including such pauses\, we obtain a broad\,
heavy-tailed distribution of transcription elongation times. When transcr
iptional pauses result in long transcription times\, we demonstrate that
this naturally leads to bursts of mRNA production and non-Poisson statisti
cs of mRNA levels. These results suggest that transcriptional pauses may
be a significant contributor to the variability in transcription rates wit
h direct implications for noise in cellular processes as well as variabili
ty between cells.\n\n//indico.ictp.it/event/a07230/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07230/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Condensed Matter Informal seminar: "Nanomagnetism and spin depende
nt transport through diluted magnetic quantum dots"
DTSTART;VALUE=DATE-TIME:20070911T100000Z
DTEND;VALUE=DATE-TIME:20070911T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07243@ictp.it
DESCRIPTION:Meticulous control of the coupling between spins is essential
to the use of magnetic nanostructures in spintronics and quantum informati
on devices. Such spin coupling has been studied in bulk ferromagnets\, t
hin films\, clusters\, nanotubes\, one dimensional monatomic metal chains
. With the development of lithography and scanning tunneling microscope (
STM) techniques\, magnetic manipulations can even be realized in quantum
dots (QDs)\, single atoms and molecules. In this talk\, I will present a
theory of magnetic exchange interactions and carrier mediated spin-spin in
teraction between Mn2+ ions in quantum dots containing electrons and magne
tic ions. We find the interaction between the electron and Mn ion to depe
nd strongly on the number of electrons. It can be switched off for closed
shell configurations and maximized for partially filled shells. The Mn-M
n interaction also depends strongly on the number of electrons. For close
d electronic shells we derive the effective RKKY interaction. For partial
ly filled shells\, finite electron spin polarizes Mn2+ ions via many-elect
ron magneto-polaron effect\, leading to effective carrier mediated ferroma
gnetic spin-spin interactions. We also explore the possibility of tailori
ng magnetism by controlling the confining potential\, particle numbers\,
temperature\, and strength of the Coulomb interactions. It is found that
the interplay of strong Coulomb interactions and quantum confinement lead
s to enhanced inhomogeneous magnetization which persists at higher tempera
tures than in the noninteracting case. The temperature of the onset of ma
gnetization can be controlled by changing the number of particles as well
as by modifying the quantum confinement and the strength of the Coulomb in
teractions. Finally\, I will show how these remarkably magnetic propertie
s are manifested in the electrical behavior of a single electron transisto
r.\n\n//indico.ictp.it/event/a07243/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a07243/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "SOC: Recent experimental
and theoretical developments"\n
DTSTART;VALUE=DATE-TIME:20070914T100000Z
DTEND;VALUE=DATE-TIME:20070914T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07244@ictp.it
DESCRIPTION:In this talk I will review the state of the art on Self-organi
zed criticality (SOC). First I will discuss some experiments on material
science and on neuro-science\, and then proceed to report on recent deve
lopments on the understanding of SOC as a phase transitions\, discussing
different viewpoints.\n\n//indico.ictp.it/event/a07244/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07244/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"Decoherence
and dephasing in quantum dots with SO(5) dynamical symmetry"\n
DTSTART;VALUE=DATE-TIME:20070920T100000Z
DTEND;VALUE=DATE-TIME:20070920T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07251@ictp.it
DESCRIPTION:Complex quantum dots are characterized by non-trivial dynamica
l symmetries SU(n)(in case of odd electron occupation) or SO(n) (in case o
f even occupation). These symmetries are activated due to interaction wit
h environment\, i.e. metallic electrons in source and drain leads\, and du
e to influence of external electrical and magnetic field. \n Incoherent
charge input signal applied to double quantum dot may be transformed into
incoherent response in Kondo-type tunnel conductance\, and the transformat
ion mechanism is intimately connected with gauge fluctuations because of t
ime-dependent violation of SO(5) symmetry. The difference between dephasi
ng and decoherence processes induced by external noise will be demonstrate
d explicitly.\n\n//indico.ictp.it/event/a07251/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07251/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on chemical physics: "Challenging the energy prob
lem by molecular simulations"\n\n
DTSTART;VALUE=DATE-TIME:20070925T100000Z
DTEND;VALUE=DATE-TIME:20070925T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07253@ictp.it
DESCRIPTION:The necessity to satisfy environmentally friendly the demand o
f energy in the World has lead to increasing interest in the use of renewa
ble and clean sources of energy. At the same time\, new sources and metho
dologies are needed to explore alternative fossil fuels (methane hydrates
and heavy oil). By using a combination of Ab initio calculations and class
ical molecular dynamics\, we have challenged the energy problem in several
directions. Firstly\, we have investigated the thermodynamics and kineti
cs of ammonia-borane (BH3NH3)*\, a promising hydrogen storage material. I
n the same line\, a study of nanoparticles of Pt* has been performed by fi
rst principles calculations to understand the size and finite surface stru
cture of chemisorption of O and OH groups for Fuel Cell applications. Al
ternatively\, we calculate the mobility and insertion potential of Li in i
norganic nanotubes as a possible electrode material in batteries*. Finall
y\, the thermodynamic and elastic properties of methane hydrates have been
investigated under the realistic thermodynamic conditions of hydrate rese
rvoirs. All together\, these examples show the importance and versatility
of molecular simulations to challenge the energy problem.\n\n//indico.ict
p.it/event/a07253/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07253/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"Criticality
in dimerized spin chains"
DTSTART;VALUE=DATE-TIME:20070927T100000Z
DTEND;VALUE=DATE-TIME:20070927T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07255@ictp.it
DESCRIPTION:Antiferromagnetic Heisenberg spin chains with alternating bond
strengths become gapless at specific values of the dimerization parameter
\, as predicted by the mapping to O(3) non-linear sigma(NLSM) with a topo
logical term. To find the location of the gapless points\, we analyticall
y and numerically study the system for various values of spin using a twis
ted boundary condition. A tunneling calculation reproduces the NLSM result
s obtained from more involved field theoretic methods. Another approach i
nvolving a certain matrix element between two Neel states provides a set o
f gapless points which not only differ significantly from the tunneling/NL
SM values\, but gives good agreement with the results of an exact diagona
lization method.\n\n//indico.ictp.it/event/a07255/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07255/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"Adiabatic q
uantum pumping in interacting systems"\n
DTSTART;VALUE=DATE-TIME:20071004T100000Z
DTEND;VALUE=DATE-TIME:20071004T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07263@ictp.it
DESCRIPTION:Adiabatic quantum pumping in noninteracting\, phase coherent s
ystems is elegantly described by Brouwer's formula. The latter expresses
geometrically the charge pumped per cycle in terms of the scattering matri
ces. Interactions within the dot\, while suppressing phase coherence\, ma
ke Brouwer's formalism inapplicable. In the presence of interactions\, is
a geometric description of pumping still possible? And what are the new\
, important physical processes brought in by the presence of interaction?
In this talk\, I will discuss recent work focusing on giving an answer to
these questions. In particular\, I will discuss the interaction correcti
ons to Brouwer's formula and show that they are related to inelastic scatt
ering events. As an illustrative example to discuss the role of inelastic
ity in pumping I will consider the effect of interaction with a bosonic ba
th on a resonant level quantum pump. Finally\, as a second example of int
eracting quantum pump\, I will describe the exact solution of the problem
of pumping in quantum dots in the Kondo regime (at the Toulouse point).\n\
n//indico.ictp.it/event/a07263/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07263/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on disorder and strong electron correlations: \n"Gap nodes
protected by topology in momentum space and quantum phase transitions"\n
DTSTART;VALUE=DATE-TIME:20071009T113000Z
DTEND;VALUE=DATE-TIME:20071009T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07265@ictp.it
DESCRIPTION:Many quantum condensed matter systems are strongly correlated
and strongly interacting fermionic systems\, which cannot be treated pertu
rbatively. However\, physics which emerges in the low-energy corner does
not depend on the complicated details of the system and is relatively sim
ple. It is determined by the nodes in the fermionic spectrum\, which are p
rotected by topology in momentum space (in some cases\, in combination wit
h the vacuum symmetry). Close to the nodes the behavior of the system bec
omes universal\; and the universality classes are determined by the toplog
ical invariants in momentum space. When one changes the parameters of the
system\, the transitions are expected to occur between the vacua with the
same symmetry but which belong to different universality classes. Differ
ent types of quantum phase transitions governed by topology in momentum sp
ace are discussed. They involve Fermi surfaces\, Fermi points\, Fermi lin
es\, and also the topological transitions between the fully gapped states
which experience intrinsic quantum Hall and spin Hall effects\, etc. The
consideration based on the momentum space topology of the Green's functio
n is general and is applicable also to the vacua of relativistic quantum f
ields. This is illustrated by the possible quantum phase transitions gove
rned by topology of nodes in the spectrum of elementary particles of Stand
ard Model.\n\n//indico.ictp.it/event/a07265/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07265/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on disorder and strong electron correlations: "On Larkin-I
mry-Ma state of superfluid 3He"
DTSTART;VALUE=DATE-TIME:20071011T100000Z
DTEND;VALUE=DATE-TIME:20071011T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07266@ictp.it
DESCRIPTION:Superfluid 3He-A shares the properties of the spin nematic cha
racterized by unit vector d of spin anisotropy and the chiral orbital ferr
omagnet characterized by vector l of the orbital angular momentum of Coope
r pairs. This doubly anisotropic superfluid\, when it is confined in aero
gel\, represents the most interesting example of a system with continuous
symmetry in the presence of random anisotropy disorder\, which is provide
d by aerogel strands.\n Recent NMR experiments allow us to discuss the sta
te of 3He-A in aerogel in terms of the Larkin-Imry-Ma (LIM) state. The LI
M state is characterized by the short-range orientational order of the l-v
ector\, while the long-range orientational order is destroyed by the colle
ctive action of the randomly oriented aerogel strings. Since 3He-A is a c
hiral superfluid\, the disordered LIM state can be represented as a syste
m of randomly distributed skyrmions -- vortices with continuous cores. Th
e characteristic distance between the vortex-skyrmions and the size of the
ir cores are determined by the LIM length which is of order of few microns
. It is much bigger than the microscopic scales -- the distance between t
he impurities-strands.\n A regular anisotropy may destroy the LIM effect\,
and this does take place when one applies a uni-axial deformation to the
aerogel sample. Even less than 1% deformation leads to the restoration of
the uniform orientation of the l-vector in the sample. As a result the
value of the transverse NMR frequency shift is enhanced by an order of mag
nitude compared to that in the LIM state. When the deformation leads to o
rientation of l along the magnetic field\, it becomes possible to study n
ovel phenomena which only occur under this arrangement and thus are not po
ssible in bulk 3He-A. One of these phenomena is the phase-coherent spin p
recession recently observed in 3He-A in the deformed aerogel. This presen
ts another realization of the Bose-Einstein condensation (BEC) of magnons\
, which is different from the magnon BEC found twenty years ago in 3He-B a
nd known as the homogeneously precessing domain. This geometry will allow
us to stabilize and observe Alice strings -- half-quantum vortices -- in
rotating 3He-A.\n\n//indico.ictp.it/event/a07266/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07266/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter seminar: "Calculation of effecti
ve magnetic interactions in Cr spinels"
DTSTART;VALUE=DATE-TIME:20071017T150000Z
DTEND;VALUE=DATE-TIME:20071017T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07270@ictp.it
DESCRIPTION:Recently\, ACr_2O_4 (A=Zn\, Cd\, Hg) compounds with a spinel c
rystal structure have attracted much attention because of their unusual ma
gnetic properties. Structural transitions to low-temperature tetragonal p
hase with a complex magnetic order or the appearance of magnetization plat
eau under application of external magnetic field are supposedly caused by
geometrical frustrations which anti-ferromagnetically (AFM) coupled Cr spi
ns experience on a pyrochlore lattice. On the other hand\, CdCr_2Se_4 spi
nel is a ferromagnetic (FM) semiconductor. In the present work effective
exchange coupling constants between Cr spins in ACr_2X_4 (A=Zn\, Cd\, Hg\;
X=O\, S\, Se) spinels are estimated by mapping the energy of spin spiral
s calculated within LSDA and LSDA+U approximations onto an effective Heise
nberg model. The calculations reproduce the change of the sign of the exc
hange coupling between nearest Cr neighbors from AFM in O-based spinels to
FM in S and Se based ones. It is shown that the AFM nearest neighbor cou
pling in ACr_2O_4$ is determined mainly by direct hopping between Cr t_{2g
} electrons whereas the FM coupling S(Se)-based spinels is caused by Cr t_
{2g}--X p--Cr t_{eg} hybridization.\n\n//indico.ictp.it/event/a07270/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07270/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder ad strong electron correlations "Superconducti
ng pumps and geometric phases"\n
DTSTART;VALUE=DATE-TIME:20071018T100000Z
DTEND;VALUE=DATE-TIME:20071018T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07274@ictp.it
DESCRIPTION:I will discuss how geometric phases emerge in superconducting
nanocircuits. Depending on the design both the abelian and non-abelian ve
rsions can be realized. I will further discuss their relation with Cooper
pair pumping and present a proposal where non-abelian effects can be dete
cted in the pumped charge.\n\n//indico.ictp.it/event/a07274/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07274/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/Democritos Informal Seinar on Chemical Physics: "Theore
tical studies of major earth and planetary materials"\n
DTSTART;VALUE=DATE-TIME:20071023T100000Z
DTEND;VALUE=DATE-TIME:20071023T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07279@ictp.it
DESCRIPTION:We employ first-principles calculations based on the density f
unctional theory (DFT) and density-functional perturbation theory (DFPT) t
o study several of the major constituents of the terrestrial and icy plane
ts. \nIn the first part\, we use the latest theoretical developments of th
e DFT and DFPT and their practical implementations in the ABINIT package t
o determine the phase diagram\, the compressibility\, the high-pressure el
astic constants and the Raman spectra for (Mg\,Fe\,Al)(Si\,Al)O3 perovskit
e and post-perovskite. The elastic constants determined from DFPT and from
the stress-strain fits differ by only a few GPa\, e.g. less than 5 GPa fo
r MgSiO3 perovskite\, and they fall within 10% of the experimental values.
The calculations of the Raman spectra are even more spectacular\, given t
he extreme requirements for convergence and accuracy of dielectric propert
ies\, usually hard to obtain. The agreement between linear-response and ex
periment is excellent for both peak position and intensity. For example th
e same three main groups of peaks in both theory and experiment characteri
ze the Raman spectra of MgSiO3 perovskite. This made us confident of the a
ccuracy of our results and we proposed the Raman spectra of the post-perov
skite\, characterized by only one main peak at high pressure. Thus Raman s
pectroscopy can be used as an identification tool for the perovskite to po
st-perovskite phase transition in high-pressure experiments. In the same t
heoretical framework we briefly discuss the pressure variation of the Rama
n spectra of alumina polymorphs. \nIn the second part we discuss the phase
diagram of solid nitrogen. Nitrogen phase diagram is characterized by sev
eral disordered and ordered molecular structures at low pressures and an a
tomic structure at high pressures. Here\, we propose a new molecular phase
which can be a link in the transition path between molecular and atomic n
itrogen. We also study in detail the dynamical and the spectroscopic prope
rties of atomic nitrogen.\n\n//indico.ictp.it/event/a07279/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07279/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Semianr on disorder and strong electron correlations: "Non-linear
transport in a two dimensional electron system"\n
DTSTART;VALUE=DATE-TIME:20071025T100000Z
DTEND;VALUE=DATE-TIME:20071025T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07280@ictp.it
DESCRIPTION:One of the most exciting recent discoveries in condensed matte
r physics is the observation of magnetoresistance oscillations and zero re
sistance states of a two dimensional electron system (2DES).\nFor a micros
copic description of this phenomenon I will introduce a quantum kinetic eq
uation for a two-dimensional electron gas. This equation can be used to c
alculate all transport characteristics of 2DES in magnetic fields\, includ
ing Shubnikov - de Haas oscillations\, smooth part of the magnetoresistan
ce\, and non-linear electric current in response to applied electric field
s. I will describe the components of the kinetic equation in terms of a s
emiclassical picture of electrons moving along cyclotron trajectories. I
will apply this equation to analyze the current-voltage characteristic of
a 2DES\, compare theoretical predictions with experimental data\, and outl
ine potential future experiments.\n\n//indico.ictp.it/event/a07280/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07280/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/Democritos Informal Seminar on Chemical Physics\n"Patch
y colloidal particles: The role of the valence in the formation of gels"\n
DTSTART;VALUE=DATE-TIME:20071031T150000Z
DTEND;VALUE=DATE-TIME:20071031T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07281@ictp.it
DESCRIPTION:I will discuss thermodynamic and dynamic properties of simple
models of particles interacting via a small number of localized patches.
I will show that the resulting reduced number of bonded neighbors has in
teresting consequences on the thermodynamic of the system. More specifical
ly\,\n(i) the region of the phase diagram where liquid-gas coexistence is
observed\nis significantly reduced as compared to the isotropic interactio
n case.\n(ii) the wider region of stability of the liquid phase favors the
establishment of a homogeneous disordered material at small packing frac
tion\, which can be named accordingly "equilibrium gels" or "network glas
s".\n(iii) it becomes possible to generate liquid states (i.e. states wit
h temperature lower than the liquid-gas critical temperature) with a vanis
hing occupied packing fraction\, a case can not be realized with spherical
ly interacting particles\;\nFinally\, I will show that for particles with
a small number of patches it is possible to derive a fully predictive para
meter-free theory of equilibrium self-assembly by combining the Wertheim t
heory for associating liquids with the Flory-Stockmayer approach for chemi
cal gelation.\n\n//indico.ictp.it/event/a07281/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07281/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Interplay o
f Coulomb and electron-phonon interactions in graphene"\n
DTSTART;VALUE=DATE-TIME:20071108T100000Z
DTEND;VALUE=DATE-TIME:20071108T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07290@ictp.it
DESCRIPTION:Electron-phonon coupling in graphene is currently a subject of
intense research. Theoretically\, the coupling constants are usually cal
culated using density-functional theory (DFT)\, where the exchange (Fock)
term is treated in the local density approximation\, or the generalized gr
adient approximation.\nIn this work we consider mutual effect of weak elec
tron-phonon and strong Coulomb interactions on each other by summing up le
ading logarithmic corrections via the renormalization group approach\, whi
ch goes beyond Hartree-Fock approximation. We find that coupling constant
s to different phonon modes are renormalized differently\, which explains
the experimentally observed intensities of Raman peaks.\n\n//indico.ictp.i
t/event/a07290/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07290/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SEMINAR on Disorder and strong electron correlations: "Ladders and
Bose-Einstein condensation in spin systems"\n
DTSTART;VALUE=DATE-TIME:20071115T100000Z
DTEND;VALUE=DATE-TIME:20071115T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07295@ictp.it
DESCRIPTION:The phenomenon of Bose-Einstein condensation is a fascinating
one. It occurs in several systems both in condensed matter and also in col
d atomic gases. How the interactions among the particles affect this tran
sition is of course a very important question. In that respect\, localized
spin systems provide a marvelous opportunity to study the BEC of strongl
y correlated bosons\, since spins 1/2\, or spin dimers can be viewed as
hard core bosons. One the other hand in one dimension it is well known tha
t spins behave more as fermions than as bosons.\nUnderstanding the interpl
ay between these two limit is thus a challenging question. Recently a com
pound which is a good realization of ladders has been experimentally stud
ied and is a good playground to tackle these issues. I will thus review th
e above physics of ladders and BEC in spin systems\, and discuss the ques
tion of the dimensional crossover and its experimental consequences for q
uantities such as the Nuclear Magnetic Resonance in such systems.\n\n//ind
ico.ictp.it/event/a07295/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07295/
END:VEVENT
BEGIN:VEVENT
SUMMARY:INFORMAL SEMINAR on Statistical Physics:" Many-Body Localization
"
DTSTART;VALUE=DATE-TIME:20071120T113000Z
DTEND;VALUE=DATE-TIME:20071120T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07297@ictp.it
DESCRIPTION:We consider low-temperature behavior of weakly interacting ele
ctrons in disordered conductors in the regime when all single-particle eig
enstates are localized by the quenched disorder. The key result is that in
the absence of coupling of the electrons to any external bath dc electric
al conductivity exactly vanishes as long as the temperature T does not exc
eed some finite value T_c. At the same time\, it can be also proven that a
t high enough T the conductivity is finite. These two statement simply tha
t the system undergoes a finite temperature metal-insulator transition\, w
hich can be viewed as Anderson-like localization of many-body wave functio
ns in the Fock space. As a result\, in the insulating phase electron-elect
ron interaction alone is unable to cause the relaxation and establish the
thermal equilibrium.\n\n//indico.ictp.it/event/a07297/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07297/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SPECIAL SEMINAR on Statistical Physics: " System level dynamics
and robustness of the genetic network regulating E.coli metabolism "
DTSTART;VALUE=DATE-TIME:20071120T133000Z
DTEND;VALUE=DATE-TIME:20071120T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07298@ictp.it
DESCRIPTION:In this talk\, I will present some of the results obtained by
studying the large scale transcriptional regulatory network controlling E.
coli metabolism containing 583 genes and 96 external metabolites as a Boo
lean dynamical system. We have studied how the attractors of the boolean d
ynamical system depend on the initial condition of the genes and on variou
s environmental conditions. We find that the nature of the attractors endo
ws the cell with both stability for a fixed environment and flexibility to
adapt to changes in the environment. We comment on design features of the
system that are responsible for these observed system level properties. I
n particular\, I will reflect upon our results obtained by studying this r
eal genetic network as opposed to those obtained earlier by studying rando
m boolean networks.\n\n//indico.ictp.it/event/a07298/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a07298/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA CONDENSED MATTER SEMINARS: "Quantum Integrable Sy
stems in Growth Problems"
DTSTART;VALUE=DATE-TIME:20071121T150000Z
DTEND;VALUE=DATE-TIME:20071121T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07296@ictp.it
DESCRIPTION:We will review connections between the stochastic and determin
istic Growth Problems in 2 dimensions (such as Diffusion Limited Aggregati
on and Laplacian Growth Problem) and theory of finite and infinite dimensi
onal integrable systems.\n\nIn particular\, we will present our recent res
ults relating the Elliptic Growth free boundary problems and theory of alg
ebraically integrable Calogero-Moser type systems.\n\nFinally\, we'll disc
uss prospectives in finding correspondence between integrable statistical
field models and DLA type problems.\n\n//indico.ictp.it/event/a07296/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07296/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Dynamic Exploration
of the Internet: modelization and biases"
DTSTART;VALUE=DATE-TIME:20071127T113000Z
DTEND;VALUE=DATE-TIME:20071127T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07300@ictp.it
DESCRIPTION:An accurate knowledge of Internet's topology is relevant to im
prove its efficiency and robustness. Internet's mapping projects are based
on collecting and merging several shortest paths from a set of sources to
a set of destinations. I will show that these processes may generate seve
re sampling biases depending on the topological properties of the underlyi
ng network. The results provide some qualitative criterion useful in the a
nalysis of experimental data. Finally\, I will discuss possible techniques
in order to correct sampling biases in network inference.\n\n//indico.ict
p.it/event/a07300/
LOCATION:SISSA - Aula D
URL://indico.ictp.it/event/a07300/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SEMINAR on Disorder and strong electron correlations: "Dephasing b
y non-Gaussian noise"\n
DTSTART;VALUE=DATE-TIME:20071129T100000Z
DTEND;VALUE=DATE-TIME:20071129T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07309@ictp.it
DESCRIPTION:The usual models for dissipative environments involve a bath o
f harmonic oscillators\, producing Gaussian fluctuations. However\, modern
experiments on dephasing in qubits and electronic interferometers indicat
e strong coupling to non-Gaussian quantum noise. Most strikingly\, the coh
erence (interference contrast) may oscillate as a function of time\, volta
ge\, and other control parameters. We present the theory behind a recent "
controlled dephasing" experiment involving an electronic Mach-Zehnder inte
rferometer strongly coupled to the non-Gaussian shot noise of a detector e
dge channel. Visibility oscillations are predicted (and experimentally fou
nd) for the coupling strength between system and bath exceeding a certain
threshold. We argue that this is a genuine and generic feature of non-Ga
ussian noise.\n\n//indico.ictp.it/event/a07309/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07309/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: " The Stefan Boltzma
nn law in a small box and the high-temperature gluon gas "\n
DTSTART;VALUE=DATE-TIME:20071204T113000Z
DTEND;VALUE=DATE-TIME:20071204T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07313@ictp.it
DESCRIPTION:The blackbody radiation in thermal equilibrium at a temperatur
e T in a box L^3 with periodic boundary conditions is affected by strong f
inite-size effects which can be expressed in a closed form in terms of the
dimensionless parameter LT. These have to be taken into account for a cor
rect interpretation of the numerical simulations of gluon gas at high temp
erature.\n\n//indico.ictp.it/event/a07313/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07313/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA CONDENSED MATTER SEMINARS: "Lattice distortion an
d Raman scattering of hcp rare gas solids under pressure"
DTSTART;VALUE=DATE-TIME:20071205T150000Z
DTEND;VALUE=DATE-TIME:20071205T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07315@ictp.it
DESCRIPTION://indico.ictp.it/event/a07315/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07315/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SEMINAR on Disorder and strong electron correlations:"Transport of
interacting electrons through a potential barrier: nonperturbative RG app
roach"\n
DTSTART;VALUE=DATE-TIME:20071206T100000Z
DTEND;VALUE=DATE-TIME:20071206T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07316@ictp.it
DESCRIPTION:We calculate the linear response conductance of electrons in a
Luttinger liquid with arbitrary interaction g_{2}\, and subject to a pote
ntial barrier of arbitrary strength\, as a function of temperature and/or
the length of interaction region. Our result agrees with known limiting ca
ses. We first map the Hamiltonian in the basis of scattering states into a
n effective low energy Hamiltonian in current algebra form. Analyzing the
perturbation theory in the fermionic representation the diagrams contribut
ing to the renormalization group (RG) beta-function are identified. The un
iversal part of beta-function is given by a ladder series and is summed to
all orders in g_{2}. The RG-equation for temperature dependent conductan
ce is solved analytically. A non-universal part of beta-function beyond t
he ladder series is discussed and compared to the recent exact solution of
the problem.\n\n//indico.ictp.it/event/a07316/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07316/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SEMINAR on Disorder and strong electron correlations:"Spin Hall ef
fects in HgTe Quantum Well Structures"\n\n
DTSTART;VALUE=DATE-TIME:20071206T150000Z
DTEND;VALUE=DATE-TIME:20071206T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07317@ictp.it
DESCRIPTION:Spin-orbit interaction (SOI) in 2DEGs causes many interesting
and potentially useful effects\, such as the generation of an intrinsic sp
in accumulation polarized normal to the 2DEG at the edges\, caused by the
presently very topical spin-Hall effect [1]. So far no direct evidence for
the intrinsic SHE has been obtained by transport experiments. Here\, we d
emonstrate that in specially designed nanostructures [2]\, which are base
d on narrow gap HgTe type-III quantum wells (QW)\, a detection of the spin
signal is possible via voltage measurements. \nRecently\, it was pointed
out that inverted HgTe QW structurescan be regarded as non-trivial insula
tors[3]\, in which the quantum spin Hall insulator state[4] should occur.
In this state\, a pair of spin polarized helical edge channels develops
when the bulk of the material is insulating\, leading to a quantized cond
uctance. We will discuss our recent transport measurements on gated low d
ensity HgTe QWs that yield a first evidence for the existence of this effe
ct.\n\n//indico.ictp.it/event/a07317/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07317/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR:"How scaling and mark
et efficiency determine the irreversible evolution of an index"\n
DTSTART;VALUE=DATE-TIME:20071211T113000Z
DTEND;VALUE=DATE-TIME:20071211T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07319@ictp.it
DESCRIPTION:In setting up a stochastic description of the time evolution o
f a financial index\, the challenge consists in devising a model compatibl
e with all stylized facts emerging from the analysis of financial time ser
ies and providing a reliable basis for simulating such series. Based on co
nstraints imposed by market efficiency and on an inhomogeneous-time genera
lization of standard simple scaling\, we propose an analytical model which
accounts simultaneously for empirical results like the linear decorrelati
on of successive returns\, the power law dependence on time of the volatil
ity autocorrelation function\, and the multiscaling associated to this dep
endence. In addition\, our approach gives a justification and a quantitati
ve assessment of the irreversible character of the index dynamics. This ir
reversibility enters as a key ingredient in a novel simulation strategy of
index evolution which demonstrates the predictive potential of the model.
\n\n//indico.ictp.it/event/a07319/
LOCATION:Lecture Room D - SISSA Main Blg
URL://indico.ictp.it/event/a07319/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SEMINAR on Disorder and strong electron correlations:"A few electr
on triple quantum dot and phonon mediated transport of electrons in nano c
ircuits"\n
DTSTART;VALUE=DATE-TIME:20071213T100000Z
DTEND;VALUE=DATE-TIME:20071213T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07323@ictp.it
DESCRIPTION:Abstract\nSolid state based quantum dots (QD) are heavily disc
ussed for applications as qubits\, but also provide a beautiful playground
for basic research on artificial molecules. First\, concepts needed to un
derstand transport and charge spectroscopy measurements on coupled QDs wil
l be developed. Then experimental results on a few electron triple QD\, a
double QD quantum ratchet and interaction mechanisms involved are discusse
d. \nOur few electron serial triple QD is electrostatically defined in a s
tandard GaAs/AlGaAs heterostructure containing a two-dimensional electron
system. Ground state stability diagrams detected with a single quantum poi
nt contact (QPC) demonstrate complete control of the triple QDs charge con
figuration in the few electron regime. The complex interplay between charg
e states of the three coupled QDs near points of high degeneracy will be d
iscussed. In this regime we observe electron transport through the three Q
Ds reflecting quantum cellular automata physics. \nThe remainder of the ta
lk will be devoted to the interaction of a strongly driven QPC with anothe
r unbiased QPC or a double QD. These experiments can be seen in the contex
t of back-action of a charge detector (the QPC) onto a qubit (the double Q
D). Using the strongly driven QPC as non-equilibrium energy source we real
ize a double QD quantum ratchet. A second experiment involving two QPCs il
luminates the possible role of electron-phonon interaction in such devices
.\n\n//indico.ictp.it/event/a07323/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a07323/
END:VEVENT
BEGIN:VEVENT
SUMMARY:INFORMAL SEMINAR on Statistical Physics: " Network Games "
DTSTART;VALUE=DATE-TIME:20071214T100000Z
DTEND;VALUE=DATE-TIME:20071214T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a07318@ictp.it
DESCRIPTION:In a variety of contexts\, including things like decisions of
which products to buy\, whether to become informed about political candida
tes\, or whether to become educated\, peoples' decisions are heavily infl
uenced by their friends and neighbors. A framework is developed to analyz
e such decision making and strategic interactions when embedded in a socia
l network of connections. Results characterize how the network structure\,
an individual's position within the network\, the strategic structure of
the games and decisions\, and the level of information\, shape behavior.\n
\n//indico.ictp.it/event/a07318/
LOCATION:ICTP Main Building Lecture Room C
URL://indico.ictp.it/event/a07318/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Broken and emerging
symmetries of turbulence"
DTSTART;VALUE=DATE-TIME:20080115T113000Z
DTEND;VALUE=DATE-TIME:20080115T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a083@ictp.it
DESCRIPTION:This is a review of most fundamental (symmetry) aspects of tur
bulence for a physical audience. To excite turbulence\, one needs an exte
rnal pumping\; to keep it in a steady state one needs dissipation. Pumpin
g and dissipation break symmetries like time-reversibility\, isotropy\, sc
ale invariance. Since pumping and dissipation act on vastly different sca
les\, the question appears what are the statistical properties of a system
at the intermediate scales (called inertial interval or transparency wind
ow). I shall describe both anomalies (when the symmetry is not restored
even when the symmetry-breaking factor goes to zero) and emerging symmetri
es like conformal invariance. In the latter case\, by using the language o
f Schramm-Loewner Evolution for analysis of fractal clusters\, one discove
rs a surprising similarity between critical phenomena and turbulence.\n\n/
/indico.ictp.it/event/a083/
LOCATION:SISSA - Lecture Room 'D'
URL://indico.ictp.it/event/a083/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Spin models on rand
om graphs with controlled topologies beyond degree constraints"
DTSTART;VALUE=DATE-TIME:20080116T103000Z
DTEND;VALUE=DATE-TIME:20080116T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a081@ictp.it
DESCRIPTION:We study Ising spin models on finitely connected random intera
ction graphs which are drawn from an ensemble in which not only the degree
distribution p(k) can be chosen arbitrarily\, but which allows for furthe
r fine-tuning of the topology via preferential attachment of edges on the
basis of an arbitrary function Q(k\,k') of the degrees of the vertices inv
olved. We solve these models using finite connectivity equilibrium replica
theory\, within the replica symmetric ansatz. In our ensemble of graphs\,
phase diagrams of the spin system are found to depend no longer only on t
he chosen degree distribution\, but also on the choice made for Q(k\,k').
The increased ability to control interaction topology in solvable models b
eyond prescribing only the degree distribution of the interaction graph en
ables a more accurate modeling of real-world interacting particle systems
by spin systems on suitably defined random graphs.\n\n//indico.ictp.it/eve
nt/a081/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a081/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Dirac fermi
ons in a power-law correlated random vector potential"\n
DTSTART;VALUE=DATE-TIME:20080117T100000Z
DTEND;VALUE=DATE-TIME:20080117T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a086@ictp.it
DESCRIPTION:We study localization properties of two-dimensional Dirac ferm
ions subject to a power-law correlated random vector potential describing\
, e.g.\, the effect of "ripples" in graphene. By using a variety of techn
iques (low-order perturbation theory\, self-consistent Born approximation\
, replicas\, and supersymmetry) we compute the low-energy density of state
s and discuss a possible (pre)localization of the entire single particle s
pectrum.\n\n//indico.ictp.it/event/a086/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a086/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Field theoretical a
pproach to layered superconductors"\n
DTSTART;VALUE=DATE-TIME:20080122T113000Z
DTEND;VALUE=DATE-TIME:20080122T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0811@ictp.it
DESCRIPTION:Typical high transition temperature superconductors consist of
copper-oxide superconducting planes separated by insulating layers. The s
uperconducting layers are coupled by Josephson and electromagnetic interac
tions. Although\, the microscopic theory of high T_c superconductivity has
not been constructed yet\, the phenomenological description is well-estab
lished. The vortex dynamics of a 2D (uncharged) superfluid film can be des
cribed by the following models which are assumed to belong to the the same
universality class: the two-dimensional sine--Gordon field theory (2D--SG
)\, the XY spin model (2D--XY) and the 2D-Coulomb gas. For charged 2D fil
ms\, i.e. for superconducting thin films\, the vortex behavior is describe
d by the massive 2D--SG\, the frustrated 2D--XY and the 2D--Yukawa gas. Th
e gas of topological excitations and the equivalent spin model of a system
of coupled layers is known for the Josephson and for the magnetically cou
pled case\, however\, no field theoretical model has been constructed.\n\n
We propose a quantum field theoretical approach to the vortex dynamics of
magnetically coupled layered superconductors by constructing a two-dimensi
onal multi-layer sine-Gordon type model which we map onto a gas of topolog
ical excitations. The known interaction potentials of magnetically couple
d vortices are consistently obtained from our field-theoretical analysis.
Originally\, this layered SG model has been introduced as the bosonised v
ersion of the multi-flavor Schwinger model\, and\, consequently\, it has b
een used to study quark confinement. We analyze the phase structure of th
e multi-layer sine--Gordon model by functional renormalization group metho
ds.\n\n//indico.ictp.it/event/a0811/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0811/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SEMINAR on Disorder and strong electron correlations: "Diagrammati
c Monte Carlo for resonant fermions "\n
DTSTART;VALUE=DATE-TIME:20080124T100000Z
DTEND;VALUE=DATE-TIME:20080124T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0818@ictp.it
DESCRIPTION:I will discuss two different Diagrammatic Monte Carlo schemes
for solving the problem of the BCS-BEC crossover in a Fermi gas with reson
ant attractive interactions (the so-called zero-range universal limit). On
e is based on summation of relevant Feynman diagrams for the partition fun
ction of up to several hundred fermions. We determine the normal-superflu
id transition temperature in the BCS-BEC crossover region and unambiguous
ly confirm that the maximum of Tc is on the Bose –side and at unitarity
T_c/E_F=0.152(7) (in disagreement with other groups!) . The other scheme
is based on direct summation of Feynman diagram for the proper self-energy
. This approach is used to solve the problem of a single spin-down fermion
resonantly interacting with the Fermi gas of spin-up particles. Though th
e original series based on bare propagators are sign-alternating and often
divergent one can still determine the answer behind them by using two str
ategies (separately or together): (i) using proper series re-summation tec
hniques\, and (ii) introducing renormalized propagators which are defined
in terms of the simulated proper self-energy\, i.e. making the entire sche
me self-consistent. Our solution is important for understanding the phase
diagram and properties of the BCS-BEC crossover in the strongly imbalanced
regime. On the technical side\, we develop a generic sign-problem toleran
t method for exact numerical solution of polaron-type models\, and\, possi
bly\, of the interacting many-body Hamiltonians.\n\n//indico.ictp.it/event
/a0818/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0818/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Matrix models in th
e quantum Hall effect"
DTSTART;VALUE=DATE-TIME:20080129T120000Z
DTEND;VALUE=DATE-TIME:20080129T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0821@ictp.it
DESCRIPTION:We discuss a quantum-mechanical model with matrix variables th
at has been originally introduced for D0-branes in string theory. \nUpon r
eplacing Hall electrons with D0-branes\, the model naturally accounts for
the Laughlin and Jain wave functions of phenomenological approaches. The m
atrix model could provide another effective field theory of the fractional
quantum Hall effect.\n\n//indico.ictp.it/event/a0821/
LOCATION:ICTP
URL://indico.ictp.it/event/a0821/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar:"Quantum electron gla
sses and electron assisted hopping"\n
DTSTART;VALUE=DATE-TIME:20080201T100000Z
DTEND;VALUE=DATE-TIME:20080201T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0825@ictp.it
DESCRIPTION:Insulators close to the metal insulator transition exhibit int
eresting collective electronic phenomena which are still rather poorly und
erstood. A prominent feature in such systems is the purely electronic na
ture of activated transport apparent in experiments\, which is inconsisten
t with the theory of phonon-assisted hopping conduction and thus has remai
ned an unexplained puzzle for decades. The situation became even less cle
ar when recently theories of many body localization predicted a metal insu
lator transition at finite temperature for interacting electrons that are
decoupled from phonons.\nIn this talk I will address this problem for Ande
rson insulators with a single-particle localization length much larger tha
n the mean distance between electrons. Under these circumstances Coulomb
interactions drive the electrons into a strongly correlated quantum glass
phase with non-trivial collective behavior. I will show that a typical me
tastable state exhibits a gapless spectrum of collective excitations which
act as a bath with which individual electrons can exchange energy. In 2D
systems\, this results in a hopping transport mechanism with a nearly uni
versal pre-exponential factor of order e2/h. This is in good agreement wi
th many recent experiments.\n\n//indico.ictp.it/event/a0825/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0825/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Arctic curves for t
he Domain Wall Six-Vertex Model "\n
DTSTART;VALUE=DATE-TIME:20080205T113000Z
DTEND;VALUE=DATE-TIME:20080205T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0829@ictp.it
DESCRIPTION:The Arctic Circle Theorem (Jockusch-Propp-Shor) concerns a mod
el of domino tiling with peculiar boundary conditions\, exhibiting phase s
eparation\, with the emergence of `limit shapes' and `arctic curves'. The
computation of such objects\, and the characterization of their fluctuatio
ns\, has been performed for several other models (Propp\, Kenyon\, Resheti
khin\, Okounkov)\, with deep implication in algebraic combinatorics and al
gebraic geometry. However all such models can be viewed as models of dimer
s\, i.e. of discrete free fermions. The most natural generalization of suc
h models\, including an interaction\, is provided by the Domain Wall Six-V
ertex Model. We here derive\, for this model with generic values of its pa
rameter\, the exact analytic expression of the arctic curves\, and charact
erize their fluctuations\, thus extending the Arctic Circle Theorem beyond
the dimer (free fermion) case.\n\n//indico.ictp.it/event/a0829/
LOCATION:SISSA\, Lecture Room 'D'
URL://indico.ictp.it/event/a0829/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Statistical Physics: "Dynamics of k-core perco
lation"
DTSTART;VALUE=DATE-TIME:20080205T140000Z
DTEND;VALUE=DATE-TIME:20080205T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0830@ictp.it
DESCRIPTION:We shall discuss the following problem: A fully occupied latti
ce is subjected to a sequence of random attacks. Each attack removes a si
te at random and recursively removes all other sites that have less than k
nearest neighbors. Random attacks continue till the lattice is empty. T
he entire sequence of events is characterized by the size of avalanche (to
tal number of sites removed) in each attack a1\, a2\, a3\, ..... Some ques
tions of interest are: (i) the distribution of avalanche sizes\, (ii) the
size of the last avalanche that empties the lattice\, and the nature of f
luctuations just before the lattice is emptied. We attempt to answer these
questions by numerical simulations as well as exact solutions on a tree a
nd place this work in the broader context of first order phase transitions
that are preceded by critical fluctuations.\n\n//indico.ictp.it/event/a08
30/
LOCATION:ICTP New Meeting Room (former 237)
URL://indico.ictp.it/event/a0830/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and Strong Correlations: "Wishart-Laguerre ens
emble of Random Matrices"
DTSTART;VALUE=DATE-TIME:20080207T100000Z
DTEND;VALUE=DATE-TIME:20080207T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0834@ictp.it
DESCRIPTION:Introduced in 1928\, many years before the celebrated Gaussian
ensembles of\nWigner-Dyson\, the Wishart ensemble contains covariance mat
rices of a\nmaximally random data set.\nThe 'N' eigenvalues constitute a s
et of strongly correlated random\nvariables\, for which a number of\nanaly
tical results (both for finite N and for N\\to\\infty) can be derived.\nIn
the first part\, I will present general results and techniques\, and give
\ntwo examples of application:\n1) spectral properties of financial data s
ets (and Marcenko-Pastur\ndistribution).\n2) random pure entangled states
in a bipartite Hilbert space (and\ndistribution of the smallest eigenvalue
).\nIn the second part\, I concentrate on a recent result (large deviation
of\nthe maximum eigenvalue) and on some work in progress (superstatistica
l\nWishart-Laguerre ensemble). I also point out the differences between\ns
pectral results on a global (macroscopic\, non-universal)\, and local\n(mi
croscopic\, universal) scale.\n\n//indico.ictp.it/event/a0834/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0834/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Agglomeration of DN
A-looping proteins"
DTSTART;VALUE=DATE-TIME:20080212T113000Z
DTEND;VALUE=DATE-TIME:20080212T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0838@ictp.it
DESCRIPTION:The transcriptional activity is not evenly distributed inside
the cell\, but it is concentrated in focal points around so-called transcr
iption factories. The formation of transcription factories and DNA looping
are considered to be of fundamental importance for the large-scale spatia
l organization of the transcriptional activity. We propose a thermodynamic
mechanism for the formation of transcriptional foci via the joint agglome
ration of DNA-looping proteins and protein-binding domains on DNA: The com
petition between the gain in protein-DNA binding free energy and the entro
py loss due to DNA looping is argued to result in an effective attraction
between loops. A mean-field description can be solved analytically via a m
apping to a restricted random-graph ensemble. It shows the emergence of pr
otein clusters containing a finite fraction of all looping proteins. If th
e entropy loss due to a single DNA loop is high enough\, this transition i
s found to be of first order.\n\n//indico.ictp.it/event/a0838/
LOCATION:ICTP
URL://indico.ictp.it/event/a0838/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Topological quantum
computation from non-abelian anyons"\n
DTSTART;VALUE=DATE-TIME:20080219T113000Z
DTEND;VALUE=DATE-TIME:20080219T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0844@ictp.it
DESCRIPTION:I discuss how systems with non-abelian anyons can be used to b
uild a topological quantum computer. Operations are performed by braiding
the anyons\; because the outcome of braiding is a purely topological prope
rty\, such quantum computers should be robust against local errors. I will
give several examples of how such anyons arise in fractional quantum Hall
systems and in quantum loop models.\n\n//indico.ictp.it/event/a0844/
LOCATION:SISSA\, Lecture Room 'D'
URL://indico.ictp.it/event/a0844/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:\n"Josephson
junctions on inhomogeneous networks"\n
DTSTART;VALUE=DATE-TIME:20080221T100000Z
DTEND;VALUE=DATE-TIME:20080221T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0849@ictp.it
DESCRIPTION:For superconducting arrays built on an inhomogeneous architect
ure\, an enhancement of the Josephson critical current along a part of the
network has been recently observed: I will present a discussion of these
results and the comparison with the findings obtained from the Bogolyubov-
de Gennes equations. Finally\, a discussion of the behavior of statistica
l mechanics models on related inhomogeneous networks is presented.\n\n//in
dico.ictp.it/event/a0849/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0849/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Entanglement\, nonl
inear dynamics and Heisenberg limit with Bose-Einstein condensates"\n
DTSTART;VALUE=DATE-TIME:20080226T113000Z
DTEND;VALUE=DATE-TIME:20080226T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0851@ictp.it
DESCRIPTION:I introduce a sufficient condition for multi-particle entangle
ment which is also necessary and sufficient for sub shot-noise sensitivity
in the estimation of a collective rotation angle. The connection is prov
ided by the Fisher information\, which is a simple measure of statistical
distance among quantum states. I show how to produce this "useful" entang
lement with dilute Bose-Einstein condensates and discuss applications on M
ach-Zehnder interferometry with phase sensitivity at the Heisenberg limit.
\n\n//indico.ictp.it/event/a0851/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0851/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:\n"Loewner ev
olution in growth processes"
DTSTART;VALUE=DATE-TIME:20080228T100000Z
DTEND;VALUE=DATE-TIME:20080228T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0854@ictp.it
DESCRIPTION:This is an introductory review of application of deterministic
and stochastic Loewner chains in equilibrium and non-equilibrium statisti
cal mechanics and free boundary problems of fluid dynamics.\n\n//indico.ic
tp.it/event/a0854/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0854/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Ordinary differenti
al equations\, minimal models and the McNugget problem"
DTSTART;VALUE=DATE-TIME:20080304T113000Z
DTEND;VALUE=DATE-TIME:20080304T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0857@ictp.it
DESCRIPTION:Recently\, surprising links between integrable models of quant
um field theory and statistical mechanics\, and the theory of ordinary dif
ferential equations\, have been found. This talk will explain the basics
of this connection\, and then go on to outline one application to the so-
called minimal models of conformal field theory.\n\n//indico.ictp.it/event
/a0857/
LOCATION:SISSA - Lecture Room 'D'
URL://indico.ictp.it/event/a0857/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:\n"Energy loc
alization in complex networks of nonlinear oscillators: Interplay between
disorder and nonlinearity in protein dynamics "
DTSTART;VALUE=DATE-TIME:20080306T100000Z
DTEND;VALUE=DATE-TIME:20080306T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0856@ictp.it
DESCRIPTION:Discrete breathers (DB) are spatially-localized\, time-periodi
c vibrations that arise under general conditions in discrete\, extended no
nlinear systems. While much is known concerning their existence and stabi
lity in spatially periodic media\, much less is known about the interplay
of nonlinearity and spatial heterogeneity in disordered systems\, where lo
calization of vibrational energy is also fostered as a result of breaking
of translational invariance.\n\nWe introduce a coarse-grained\, topology-b
ased nonlinear network model of protein dynamics with the aim of investiga
ting the interplay of spatial disorder and nonlinearity in biological mole
cules. DB solutions\, characterized both numerically with the surface coo
ling technique and analytically\, show that localization of energy occurs
generically also in the presence of disorder\, but is a site-dependent and
\, on a larger scale\, a fold-dependent process. In particular\, we find
that\, as a sheer consequence of disorder\, a non-zero energy gap for exc
iting a DB at a given site either exists or not. Interestingly\, in the f
ormer case\, the gaps arise as a result of the impossibility of exciting
small-amplitude modes in the first place. In the latter case\, a small su
bset of linear localized modes act as accumulation points\, whereby DBs c
an be continued to arbitrary small energies\, while unavoidably approachin
g one of such normal modes.\n\nRemarkably\, our cooling simulations show
that localized modes of nonlinear origin form spontaneously in the stiffes
t parts of the structure. Analytic calculations further reveal that such
regions are also the sectors where DBs are characterized by the smallest e
nergy gaps. Besides being interesting per se\, such results provide a str
aightforward way for interpreting the recently discovered link between loc
al stiffness of proteins and enzymatic activity. They strongly suggest th
at nonlinear vibrational modes may play an important role in enzyme functi
on\, allowing for a ready energy storage channel during the catalytic proc
ess.\n\n//indico.ictp.it/event/a0856/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0856/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical phsycis seminar: "Griffiths singulari
ties in finite-dimensional spin glasses"\n
DTSTART;VALUE=DATE-TIME:20080307T100000Z
DTEND;VALUE=DATE-TIME:20080307T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0866@ictp.it
DESCRIPTION:The distribution of zeros of the partition function is studied
for the two- and three-dimensional Ising spin glasses on the complex fiel
d plane. We estimate the density of zeros on the imaginary axis by an imp
ortance-sampling Monte Carlo algorithm\, which enables us to sample very r
are events. Our result suggests that the density has an essential singula
rity at the origin\, giving the first evidence for a Griffiths singularity
in spin glass systems in equilibrium.\n\n//indico.ictp.it/event/a0866/
LOCATION:SISSA - Lecture Room 'D'
URL://indico.ictp.it/event/a0866/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Starling flocks: An
empirical study of the interaction ruling collective animal behaviour"
DTSTART;VALUE=DATE-TIME:20080311T113000Z
DTEND;VALUE=DATE-TIME:20080311T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0861@ictp.it
DESCRIPTION:Numerical models indicate that collective animal behaviour may
emerge from simple local rules of interaction among the individuals. Ho
wever\, very little is known about the nature of such interaction\, so tha
t models and theories mostly rely on aprioristic assumptions. By reconstr
ucting the three-dimensional position of individual birds in airborne floc
ks of few thousands members\, we prove that the interaction does not depen
d on the metric distance\, as most current models and theories assume\, bu
t rather on the topological distance. In fact\, we discover that each bir
d interacts on average with a fixed number of neighbours (six-seven)\, rat
her than with all neighbours within a fixed metric distance. We argue tha
t a topological interaction is indispensable to maintain flock's cohesion
against the large density changes caused by external perturbations\, typic
ally predation. We support this hypothesis by numerical simulations\, sh
owing that a topological interaction grants significantly higher cohesion
of the aggregation compared to a standard metric one.\n\n//indico.ictp.it/
event/a0861/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0861/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/Democritos Informal seminar on Chemical physics: "Struc
tures and superconductivity of selected high pressure solids"\n
DTSTART;VALUE=DATE-TIME:20080311T100000Z
DTEND;VALUE=DATE-TIME:20080311T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0867@ictp.it
DESCRIPTION:Recent achievements in synchrotron instrumentations have great
ly improved the quality of powder diffraction data obtained from a diamond
anvil cell. With structural refinement techniques\, many new structures
of solid materials at high pressures have been discovered. In a number of
solids\, these structural changes also induce metallization and lead to t
he appearance of superconductivity upon compressing. On the theoretical s
ide\, typical approaches for predicting/determining unknown high-pressure
crystal structures usually involve dynamical processes. We have tried ano
ther approach based on evolutionary algorithms proposed recently. This is
an attempt to predict the most stable crystal structure and energetically
favourable meta-stable structures without any approximation on initial st
ructures. During evolutionary procedures\, randomly generated structures
evolve gradually into lower energy phases after a few generations. We hav
e investigated the high-pressure structures of calcium and predicted two n
ew stable structures that might explain the diffraction pattern of Ca-IV a
nd Ca-V. Another example will be presented is the prediction of a metasta
ble single-bonded phase of nitrogen. The search of a synthetic strategy f
or novel materials with high-Tc has been a continuing challenge. Recently
there have been several new proposals relating superconductivity with som
e tailgate signatures for prospective candidate materials. Among these pr
oposals are (i) the occurrence of low vibrational frequencies (ii) simulta
neous occurrence of dynamical and electronic instabilities. Here we demon
strated successfully that these conditions can be satisfied in a high pres
sure phase of SnH4. We predicted this material would be superconducting w
ith a Tc close to 80 K at 120 GPa. Some other high-pressure superconducto
rs will be briefly reviewed.\n=\n* Work done in collaboration with John S.
Tse\n\n//indico.ictp.it/event/a0867/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0867/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"On statisti
cal mechanics of a single particle in random landscapes"\n
DTSTART;VALUE=DATE-TIME:20080313T100000Z
DTEND;VALUE=DATE-TIME:20080313T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0868@ictp.it
DESCRIPTION:I am going to discuss recent results of the replica approach t
o statistical mechanics of a single classical particle placed in a random
N>>1-dimensional Gaussian landscape. The particular attention will be pai
d to the case of landscapes with logarithmically growing correlations and
to its recent generalizations. Those landscapes give rise to a rich multi
fractal spatial structure of the associated Boltzmann-Gibbs measure. If t
ime allows\, I will also briefly discuss a one-dimensional variant of the
model which can be analyzed by a mapping to the Dyson's Coulomb gas. In p
articular\, in the latter case we conjecture the explicit form of the dist
ribution of the lowest minimum in such a potential.\n\n//indico.ictp.it/ev
ent/a0868/
LOCATION:ICTP Main Building Seminar Room
URL://indico.ictp.it/event/a0868/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"Topological
phase transition in an exactly solvable model"\n
DTSTART;VALUE=DATE-TIME:20080403T100000Z
DTEND;VALUE=DATE-TIME:20080403T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0882@ictp.it
DESCRIPTION:The Kitaev model is an exactly solvable spin-1/2 system on the
honeycomb lattice. It undergoes a topological phase transition from a ph
ase with an energy gap carrying Abelian anyons to a gapless one with non-A
belian anyons. The model is generally considered a prototype to do quantum
computation. We construct and exactly solve a three dimensional model wh
ich is a generalization of the Kitaev model. We further show that there a
re excitations localized on loops that can possibly obey nontrivial statis
tics.\n\n//indico.ictp.it/event/a0882/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0882/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Critical Casimir fo
rces"
DTSTART;VALUE=DATE-TIME:20080408T113000Z
DTEND;VALUE=DATE-TIME:20080408T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0889@ictp.it
DESCRIPTION:Long-ranged correlations in a fluid close to its critical poin
t lead to clearly identifiable effective forces on confining walls. The co
rresponding universal scaling functions are discussed for different bounda
ry conditions and geometries. The theoretical predictions are compared wit
h high precision experimental data for He4 and He3/He4 wetting films near
the superfluid phase transition as well with synchrotron scattering data f
rom classical binary liquid mixtures. Applications for colloidal suspensio
ns are discussed.\n\n//indico.ictp.it/event/a0889/
LOCATION:Lecture Room 'D'\, SISSA Main Bldg.
URL://indico.ictp.it/event/a0889/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Single-mole
cule transistors - A new perspective on the \nAnderson-Holstein model"\n
DTSTART;VALUE=DATE-TIME:20080410T143000Z
DTEND;VALUE=DATE-TIME:20080410T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0890@ictp.it
DESCRIPTION:Following up on a long-standing suggestion by Aviram and Ratne
r\, experimenters have recently made great efforts in contacting and gatin
g single molecules. Such experiments pose new theoretical challenges not
only because typical energy and length scales are different from those in
conventional nanostructures such as quantum dots\, but also because they i
nvolve degrees of freedom specific to molecular structures such as discret
e vibrational modes or localized spins. In this talk\, I will discuss sev
eral situations where the coupling to vibrational modes is predicted to dr
amatically affect the transport properties. Specifically\, I will show th
at electron-vibron coupling can induce self-similar avalanche transport as
well astunneling of electron pairs\n\n//indico.ictp.it/event/a0890/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0890/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Periodic orbits\, l
ocalization in normal mode space\, and the Fermi-Pasta-Ulam problem"
DTSTART;VALUE=DATE-TIME:20080414T143000Z
DTEND;VALUE=DATE-TIME:20080414T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0893@ictp.it
DESCRIPTION:In 1955 Fermi\, Pasta and Ulam (FPU) reported on the nonequipa
rtition of a nonlinear atomic chain\, with initially one normal mode excit
ed. Modern computational studies show\, that on a first\, relatively shor
t\, time scale the energy is distributed among a few neighbouring modes in
modal space\, with more distant modes being exponentially weakly excited
- i.e.\, one observes localization in normal mode space. On a much larger
second time scale (which was not reachable wih the MANIAC I)\, the tail m
odes are slowly growing\, and finally the system does equilibrate. The pro
blem then is to explain i) the exponential localization of energy in modal
space on intermediate time scales\, and ii) the way the time scales depen
d on the essential parameters (wave number\, energy density). Despite its
strong impact on nonlinear dynamics and statistical physics\, the paradox
remained essentially unexplained for decades - ideal grounds for the appe
arance of myths.\nRecent studies show that the model allows for exact time
-periodic solutions (q-breathers)\, which are exponentially localized in t
he space of normal modes. The trajectory initially computed by FPU is a sl
ight perturbation away from an exact q-breather orbit. Consequently most o
f the key observations related to the FPU problem (localization of energy
in normal mode space for long times\, recurrence on relatively short times
\, system size and energy thresholds) are captured by the properties of q
-breathers and the phase space flow nearby. The underlying concept is muc
h more general\, and can be easily extended to two-and three-dimensional f
inite lattices. A scaling approach leads to nontrivial predictions in the
limit of infinite system sizes.\n\n//indico.ictp.it/event/a0893/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0893/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed matter seminar: " New approaches in mol
ecular dynamics: From stochastic thermostats to rare-event sampling "
DTSTART;VALUE=DATE-TIME:20080415T100000Z
DTEND;VALUE=DATE-TIME:20080415T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0891@ictp.it
DESCRIPTION:A new molecular-dynamics algorithm for sampling the canonical
distribution will be presented [1].\nIn this approach the velocities of al
l the particles are rescaled by a properly chosen random factor.\nIts prop
erties will be illustrated for Lennard-Jones and water in the solid and li
quid phases.\nNext\, a method for determining the free-energy dependence o
n a selected number of order parameters using an adaptive bias will be int
roduced [2]. This method has metadynamics and canonical sampling as limiti
ng cases and allows for easy and rigorous error control.\nFinally\, a new
technique based on a combination of metadynamics and parallel-tempering wi
ll be discussed [3].\nThis scheme will be shown to be an affordable method
for the computation of free-energy landscapes in biomolecules. The foldi
ng of the beta-hairpin in explicit water will then be used to illustrate t
he power of this technique.\n[1] G. Bussi\, D. Donadio and M. Parrinello\,
J. Chem. Phys. 126\, 014101 (2007)\n[2] A. Barducci\, G. Bussi and M. Par
rinello\, Phys. Rev. Lett. 100\, 020603 (2008).\n[3] G. Bussi\, F. L. Ger
vasio\, A. Laio and M. Parrinello\, J. Am. Chem. Soc. 128\, 13435 (2006).
\n\n//indico.ictp.it/event/a0891/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0891/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar "From holonomy of the
non-critical Ising model form factors to n-fold integrals and the theory
of elliptic curves\, moduli spaces\,... and beyond"
DTSTART;VALUE=DATE-TIME:20080415T113000Z
DTEND;VALUE=DATE-TIME:20080415T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0892@ictp.it
DESCRIPTION:Abstract\n\nWe recall the form factors of the two-point diagon
al correlation function of the Ising model on the square lattice and their
associated linear differential equations which exhibit both a "Russian-do
ll'' nesting\, and a decomposition of the linear differential operators a
s a direct sum of operators.\nThe scaling limit of these differential oper
ators breaks the direct sum structure but not the "Russian doll'' structu
re\, the "scaled'' linear differential operators being no longer Fuchsian
.\nWe also discuss the nature of the singularities emergingfrom this appro
ach.\n\n//indico.ictp.it/event/a0892/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0892/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SEMINAR on Disorder and strong electron correlations: "The effecti
ve mass of the charge carrier in non-polar liquid: applications to superfl
uid helium"\n\n
DTSTART;VALUE=DATE-TIME:20080417T100000Z
DTEND;VALUE=DATE-TIME:20080417T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0894@ictp.it
DESCRIPTION:We consider the problem of the effective mass of a charge carr
ier definition in non-polar viscous liquid and show how the problem of its
formal divergency can be resolved. Then the effective mass of a snowball
in superfluid Helium is revised and observed a long ago its temperature de
pendence is explained theoretically.\n\n//indico.ictp.it/event/a0894/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0894/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Semianr on Disorder and strong electron correlations: "Numerical o
bservation of Hawking radiation from acoustic black holes in atomic Bose-E
instein condensates"\n
DTSTART;VALUE=DATE-TIME:20080424T100000Z
DTEND;VALUE=DATE-TIME:20080424T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0896@ictp.it
DESCRIPTION:Although the existence of black-holes has been indirectly prov
en on astrophysical grounds\, no experimental evidence of their slow but r
elentless evaporation into Hawking radiation has been obtained yet. In th
e present talk we report numerical simulations of a condensed matter syste
m which shares many properties with gravitational black-holes\, in particu
lar the emission of a Hawking radiation: a horizon is created in a moving
cloud of ultracold atoms in the nanoKelvin range where atoms behave in a c
oherent way as a Bose-Einstein condensate\, and the presence of Hawking ra
diation is inferred from peculiar correlations of the quantum fluctuations
of the atomic density.\n\n//indico.ictp.it/event/a0896/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0896/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Statistical mechani
cs of flux distribution in metabolic networks"\n
DTSTART;VALUE=DATE-TIME:20080429T113000Z
DTEND;VALUE=DATE-TIME:20080429T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0897@ictp.it
DESCRIPTION:In recent years we have assisted to a big breakthrough in syst
em biology\, the interdisciplinary field that studies the biological prob
lems going beyond the single biomolecular framework with the description o
f the intertwined reactions between the constituent of the cell in terms o
f networks.\nIn this talk we study the problem of flux distribution in met
abolic networks by statistical mechanics methods. We will first derive th
e most probable flux distribution with intermediate metabolites at steady
state secondly we will study the flux distribution close to optimal biomas
s production. Analytical tractability of the models is possible if the pr
oblems are defined over random graphs with the same degree distribution of
the real metabolic networks. The flux distribution close to the optimal
biomass production develops a fat tail with power-law exponent independent
on the structure of the underline network in perfect agreement with bioin
foarmatics methods and in qualitative agreement with experiments. To solv
e these problems we will introduce a Gaussian Replica Symmetric Ansatz val
id for quadratic models defined on continuous variables refined on the rea
l axis\, and a new method for study cavity equations on continuous variabl
es close to a critical point.\n\n//indico.ictp.it/event/a0897/
LOCATION:SISSA Main Bldg.-Lecture Room 'D'
URL://indico.ictp.it/event/a0897/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Superfrustruation o
f lattice fermions"
DTSTART;VALUE=DATE-TIME:20080507T113000Z
DTEND;VALUE=DATE-TIME:20080507T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0898@ictp.it
DESCRIPTION:The term superfrustration refers to massive ground state degen
eracy in supersymmetric lattice models for itinerant fermions with strong
repulsive interactions\, in dimension D>1. In general\, quantum phases of
lattice fermions are hard to track\, due to lack of analytic methods and
fundamental difficulties in numerical analysis. I will show how supersymm
etry improves this situation and leads to exact results on the number and
nature of quantum gound states. Superfrustration is established by showin
g that on a variety of 2D lattices the supersymmetric model has extensive
ground state entropy. For the 2D square lattice I demonstrate the existenc
e of critical edge excitations.\n\n//indico.ictp.it/event/a0898/
LOCATION:SISSA Main Bldg.\, Lecture Room 'D'
URL://indico.ictp.it/event/a0898/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Finite- temperature
lineshapes in gapped quantum spin chains"\n
DTSTART;VALUE=DATE-TIME:20080513T113000Z
DTEND;VALUE=DATE-TIME:20080513T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08100@ictp.it
DESCRIPTION:We consider the finite-temperature dynamical suscepibility\, X
(T)\, of gapped quantum spin chains such as the integer spin Heisenberg mo
del and the transverse field Ising model. At zero temperature X in thes
e models is dominated by a delta-function line arising from the coherent p
ropagation of single particle modes. Using methods of integrable quantum
field theory we determine the evolution of the lineshape at low temperatur
es. We show that the line shape is in general asymmetric in energy. We d
iscuss the application of our results to inelastic neutron scattering expe
riments on gapped spin chain systems such as YBaNiO_5.\n\n//indico.ictp.it
/event/a08100/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08100/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: \nSeries of lectures
on: 'Singularities and asymptotics'\nFirst lecture\n"Tsunami asymptotics"
\n\n
DTSTART;VALUE=DATE-TIME:20080520T100000Z
DTEND;VALUE=DATE-TIME:20080520T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08106@ictp.it
DESCRIPTION:For most of their propagation\, tsunamis are linear dispersive
waves whose speed is limited by the depth of the ocean and which can be r
egarded as diffraction-decorated caustics in spacetime. For constant depth
\, uniform asymptotics gives a very accurate compact description of the ts
unami profile generated by an arbitrary initial disturbance. Vartiations i
n depth can focus tsunamis onto cusped caustics\, and this ‘singularity
on a singularity’ constitutes an unusual diffraction problem\, whose sol
ution indicates that focusing can amplify the tsunami energy by an order o
f magnitude.\n\n//indico.ictp.it/event/a08106/
LOCATION:SISSA Main Bldg.\, Room 'D'
URL://indico.ictp.it/event/a08106/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: \nSeries of lectures
on: 'Singularities and asymptotics'\nFirst lecture\n"Tsunami asymptotics"
\n\n
DTSTART;VALUE=DATE-TIME:20080520T100000Z
DTEND;VALUE=DATE-TIME:20080520T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08107@ictp.it
DESCRIPTION:For most of their propagation\, tsunamis are linear dispersive
waves whose speed is limited by the depth of the ocean and which can be r
egarded as diffraction-decorated caustics in spacetime. For constant depth
\, uniform asymptotics gives a very accurate compact description of the ts
unami profile generated by an arbitrary initial disturbance. Vartiations i
n depth can focus tsunamis onto cusped caustics\, and this ‘singularity
on a singularity’ constitutes an unusual diffraction problem\, whose sol
ution indicates that focusing can amplify the tsunami energy by an order o
f magnitude.\n\n//indico.ictp.it/event/a08107/
LOCATION:SISSA Main Bldg.\, Room 'D'
URL://indico.ictp.it/event/a08107/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter seminar: "Quantum physics dilemm
a"
DTSTART;VALUE=DATE-TIME:20080521T150000Z
DTEND;VALUE=DATE-TIME:20080521T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08105@ictp.it
DESCRIPTION:Through the development of quantum physics\, there was deep co
ntradiction in the concepts of understanding the quantum outcome data. Bo
hr-Heisenberg interpretation depends on nonlocality and indeterminism and
the effect of measuring instrument\, Einstein-Schrödinger and others refu
sed these interpretations and concentrated on reality and locality. Who a
re right and who are wrong? Up to nowadays no clear decision/ideas in spit
e of the very expensive sophisticated apparatus used to solve this dilemma
and to find the basis of Quantum Physics. The evidences of polarization\
, entanglement and teleportation all gave scattered results\, especially w
hen repeated. What is the role of consciousness in measurement?\nAs Aspec
t put it:" our conclusion is more a question of taste then logic"\, while
Aspelmeyer says\, nonlocality is not enough to save realism from quantum t
heory.\nSo do we go to a compromise and accept both ideas or concepts?! Th
at both are right? each in his field of experience.\n\n//indico.ictp.it/ev
ent/a08105/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08105/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Modeling th
e two-dimensional electron gas in solid state devices"\n
DTSTART;VALUE=DATE-TIME:20080522T100000Z
DTEND;VALUE=DATE-TIME:20080522T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08108@ictp.it
DESCRIPTION:The electron gas (EG)\, a collection of point charges moving i
n a homogeneous neutralizing background\, provides a far reaching paradigm
underlying our current understanding of electronic systems. Nowadays\,
quasi two-dimensional electron gases of exceedingly high mobility are rout
inely available in the best laboratories around the world. This allows fo
r the experimental investigation of the two-dimensional electron gas (2DE
G) in the strong coupling regime\, where the interplay between interaction
and disorder scattering has unexpected effects\, such as an apparent meta
l to insulator transition (MIT) which has attracted a considerable experim
ental and theoretical interest. Evidently\, fine details of the devices h
osting the quasi 2DEG play an important role in determining its properties
and should be accounted for by theory. In actual solid-states realization
s the 2DEG (i) has a finite transverse thickness\, (ii) suffers scattering
by a number of sources (scattering which in fact determines its mobility)
\, and depending on the system (iii) occupies one or two valleys\; moreov
er\, (iv) in certain AlAs quantum wells it may have an in plane anisotropi
c kinetic energy (mass tensor). A property of the 2DEG that has recently
received a lot of attention in connection with the MIT is the spin suscept
ibility χs. This measures the linear response of the electrons to an appl
ied magnetic field that couples to the electron spin\, causing a net spin
polarization. We demonstrate that the EG model is perfectly capable of des
cribing the available experimental evidence for χs once two conditions a
re met: relevant device details are included in the theoretical descripti
on and strong correlation effects are dealt with by a sufficiently accurat
e technique\, such as quantum Monte Carlo simulations (QMC). In particula
r\, we show that a perturbative account of disorder\, based on the QMC p
redictions for the clean interacting 2DEG\, yields for two-valley systems
a divergence of χs with lowering the density in excellent agreement with
the available experimental evidence for Si-MOSFETs.\n\n//indico.ictp.it/e
vent/a08108/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08108/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar:\nSeries of lectures
on: 'Singularities and asymptotics'\nSecond lecture\n"Conical diffraction:
Imaging Hamilton's diabolical point"\n
DTSTART;VALUE=DATE-TIME:20080522T133000Z
DTEND;VALUE=DATE-TIME:20080522T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08113@ictp.it
DESCRIPTION:The transformation of a narrow beam into a hollow cone when in
cident along the optic axis of a biaxial crystal\, predicted by Hamilton i
n 1832\, created a sensation when observed by Lloyd soon afterwards. It wa
s possibly the first prediction of a qualitatively new phenomenon using ma
thematics\, the first application of the concept of phase space\, and the
prototype of the conical intersections now popular in quantum chemistry. B
ut the fine structure of the light cone contains many subtle features\, sl
owly revealed by experiment\, whose definitive explanation\, involving new
mathematical asymptotics\, has been achieved only recently\, along with d
efinitive experimental test of the theory. Radically different phenomena\,
being intensively studied now\, arise when chirality and absorption are i
ncorporated in addition to biaxiality.\n\n//indico.ictp.it/event/a08113/
LOCATION:Lecture room 'D'\, SISSA Main Bldg.
URL://indico.ictp.it/event/a08113/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: \nSeries of lectures
on: 'Singularities and asymptotics'\nThird lecture\n"Polarization fingerp
rints in the clear blue sky"\n\n
DTSTART;VALUE=DATE-TIME:20080527T100000Z
DTEND;VALUE=DATE-TIME:20080527T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08114@ictp.it
DESCRIPTION:Daylight is polarized\, the strength being greatest at points
in the sky at right angles to the sun\, and zero at four points: above and
below the sun and anti-sun. The zero-polarization points are ‘fingerpri
nt’ singularities\, around which the polarization direction makes a half
-turn. Using elementary singularity theory\, the polarization pattern acro
ss the whole sky can be described in a way that fits recent observations w
ith an accuracy comparable to that of conventional elaborate multiple-scat
tering calculations. This recent work is a contribution to a story that st
arted in 1817 and has been central to our understanding of polarized light
.\n\n//indico.ictp.it/event/a08114/
LOCATION:ICTP Leonardo da Vinci Building Lecture Room B
URL://indico.ictp.it/event/a08114/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: \nSeries of lectures
on: 'Singularities and asymptotics'\nFourth lecture\n"Optical vorticultur
e"\n
DTSTART;VALUE=DATE-TIME:20080529T140000Z
DTEND;VALUE=DATE-TIME:20080529T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08117@ictp.it
DESCRIPTION:After reviewing the history\, beginning in the 1660s\, of line
s of phase and polarization singularity in light and other waves\, I will
describe our present understanding of their geometry\, and several recent
applications: to spiral phase plates (vortex choreography)\, vortex knots
and links\, ubiquity of vortices in interferometers\, and quantum cores o
f the singularities.\n\n//indico.ictp.it/event/a08117/
LOCATION:ICTP Leonardo da Vinci Building Lecture Room B
URL://indico.ictp.it/event/a08117/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: \nSeries of lectures
on: 'Singularities and asymptotics'\nFifth lecture\n"Two by two"\n
DTSTART;VALUE=DATE-TIME:20080604T140000Z
DTEND;VALUE=DATE-TIME:20080604T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08118@ictp.it
DESCRIPTION:A tutorial account of families of 2x2 matrices labelled by sev
eral parameters will concentrate on the neighbourhood of degeneracies. The
emphasis will be on the differences between hermitian and nonhermitian ma
trices. Physical phenomena where such degeneracies play a crucial role wil
l be described.\n\n//indico.ictp.it/event/a08118/
LOCATION:ICTP Leonardo da Vinci Building Lecture Room B
URL://indico.ictp.it/event/a08118/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Growing length scal
es\, configurational entropy and dynamics in glass forming liquids"\n
DTSTART;VALUE=DATE-TIME:20080604T100000Z
DTEND;VALUE=DATE-TIME:20080604T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08119@ictp.it
DESCRIPTION:The relationship between dynamics\, a growing length scale ass
ociated with cooperatively rearranging regions\, and configurational entro
py underlie the Adam-Gibbs theory of dynamics in glass forming liquids.\nW
hile the Adam-Gibbs relation between relaxation times and configurational
entropy has been widely employed to rationalize experimental and computer
simulation data\, attempts to directly study the length scales associated
with cooperatively rearranging regions have been relatively few. Fresh imp
etus in this direction comes from recent studies of spatially heterogeneou
s dynamics\, wherein analysis of spatial correlations of the mobility of p
articles allows estimation of a dynamical length. Finite size scaling is
employed in the present work to evaluate a dynamical length scale in a mod
el glass forming liquid\, whose relationship to relaxation times and confi
gurational entropy are examined. Comparison with theoretical predictions
reveal partial agreement\, and yield surprises that require further theore
tical analysis to resolve. The configurational entropy is found to determ
ine relaxation times for all temperatures and system sizes studied through
the Adam-Gibbs relation\, but the configurational entropy of cooperativel
y rearranging regions grows as the temperature is lowered\, contrary to th
e assumptions of Adam-Gibbs theory.\n\n//indico.ictp.it/event/a08119/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08119/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: \nSeries of lectures
on: 'Singularities and asymptotics'\nSixth lecture\n"Boundary-varying bou
ndary conditions: \nThe Dirichlet singularity"\n
DTSTART;VALUE=DATE-TIME:20080605T140000Z
DTEND;VALUE=DATE-TIME:20080605T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08120@ictp.it
DESCRIPTION:Waves in a two-dimensional domain with Robin (mixed) boundary
conditions that vary smoothly along the boundary exhibit unexpected phenom
ena. If the variation includes a ‘D point’ where the boundary conditio
n is Dirichlet (vanishing wavefunction)\, the system is singular. For a ci
rcle billiard\, the boundary condition fails to determine a discrete set o
f levels\, so the spectrum is continuous. For a diffraction grating define
d by periodically-varying boundary conditions on the edge of a half-plane\
, the phase of a diffracted beam amplitude remains undetermined. In both
cases\, the wavefunction on the boundary has a singularity at a D point\,
described by the polylogarithm function.\n\n//indico.ictp.it/event/a08120
/
LOCATION:ICTP Leonardo da Vinci Building Lecture Room B
URL://indico.ictp.it/event/a08120/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar:\n\nSeries of lecture
s on: 'Singularities and asymptotics'\n\nSeventh lecture\n\n" Quantum mech
anics\, chaos\, and the music of the primes "\n(duration 2 hours)\n
DTSTART;VALUE=DATE-TIME:20080610T100000Z
DTEND;VALUE=DATE-TIME:20080610T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08125@ictp.it
DESCRIPTION:The Riemann hypothesis can be interpreted as stating that the
prime numbers contain 'music'\, whose component frequencies are the Rieman
n zeros. The question "Frequencies of what?" leads to tantalizing connect
ions with the energy levels of quantum systems whose corresponding classic
al motion is chaotic. At the level of statistics\, predictions for the Ri
emann zeros based on semiclassical quantum asymptotics (with primes as per
iods of classical trajectories) have reached a high degree of accuracy and
refinement. For the zeros themselves\, the Riemann-Siegel formula and it
s improvements lead to new ways of calculating quantum levels.\n\n//indico
.ictp.it/event/a08125/
LOCATION:ICTP Leonardo da Vinci Building Lecture Room B
URL://indico.ictp.it/event/a08125/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter seminar: "Novel aspects in \nthe
rmodynamics of fuzzy interfaces"\n
DTSTART;VALUE=DATE-TIME:20080611T150000Z
DTEND;VALUE=DATE-TIME:20080611T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08124@ictp.it
DESCRIPTION:For decades the behavior of Tolman's length (a curvature-corre
ction coefficient in the surface tension [1]) has remained one of the most
controversial issues in mesoscopic thermodynamics of fluids. Moreover\, i
t was commonly believed that Tolman’s length played no significant role
in practice. However\, it was recently shown [2] that there is a thermodyn
amic relation between Tolman’s length and the thickness of the interface
on the one hand and the shape of the fluid-phase coexistence on the other
hand. In particular\, it was shown that Tolman's length strongly diverges
at the critical point of fluids with the amplitude that depends on the de
gree of asymmetry in fluid-phase coexistence. The critical divergence of T
olman’s length is universal\, originating from the mesoscopic critical f
luctuations. The fluctuations make the fluid interface fuzzy and significa
ntly change the shape of the phase coexistence. In symmetric systems\, suc
h as the lattice gas\, the curvature correction to the interfacial tension
vanishes. The divergence of the curvature correction to the interfacial t
ension is especially pronounced in polymer solutions and asymmetric polyme
r blends. Tolman’s length in polymer solutions may become as large as th
e thickness of the smooth interface\, thus playing a significant role in t
he behavior of polymer microdroplets and polymer fluids in porous media. \
n\n[1] R. C. Tolman\, J. Chem Phys. 1949\, 17\, 333.\n[2] M. A. Anisimov\,
Phys. Rev. Lett. 2007\, 98\, 035702.\n\n//indico.ictp.it/event/a08124/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08124/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar:\nSeries of lectures
on: 'Singularities and asymptotics'\n\nEighth lecture\n\n" Three recent re
sults on asymptotics of oscillations "\n
DTSTART;VALUE=DATE-TIME:20080611T100000Z
DTEND;VALUE=DATE-TIME:20080611T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08126@ictp.it
DESCRIPTION:The results are separate\, and apparently paradoxical\, and ha
ve implications for physics. First\, when two exponentials compete\, thei
r interference can be dominated by the contribution with smaller exponent.
Second\, repeated differentiation of almost all functions in a wide clas
s generates trigonometric oscillations (‘almost all functions tend to co
sx’). Third\, it is possible to find band-limited functions that oscill
ate arbitrarily faster than their fastest Fourier component (‘superoscil
lations’).\n\n//indico.ictp.it/event/a08126/
LOCATION:ICTP Leonardo da Vinci Building Lecture Room B
URL://indico.ictp.it/event/a08126/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar:\nSeries of lectures
on: 'Singularities and asymptotics'\n\nNinth (and last) lecture\n\n" Maki
ng light of mathematics "\n( a nontechnical talk\, suitable for nonscienti
sts )\n
DTSTART;VALUE=DATE-TIME:20080612T140000Z
DTEND;VALUE=DATE-TIME:20080612T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08127@ictp.it
DESCRIPTION:Many ‘mathematical phenomena’ find application and sometim
es spectacular physical illustration in the physics of light. Concepts su
ch as fractals\, catastrophe theory\, knots\, infinity\, zero\, and even w
hen 1+1 fails to equal 2\, are needed to understand rainbows\, twinkling s
tarlight\, sparkling seas\, oriental magic mirrors\, and simple experiment
s on interference\, polarization and focusing. The lecture is strongly vi
sual\, and nontechnical\, though the concepts are subtle.\n\n//indico.ictp
.it/event/a08127/
LOCATION:SISSA Main Bldg.
URL://indico.ictp.it/event/a08127/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar:\n"The instability of
coherent risk measures"
DTSTART;VALUE=DATE-TIME:20080617T100000Z
DTEND;VALUE=DATE-TIME:20080617T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08129@ictp.it
DESCRIPTION:It is shown that the axioms for coherent risk measures imply t
hat whenever a dominant portfolio can be formed on a given sample (which h
appens with finite probability even for large samples)\, then portfolio op
timization cannot be performed under any coherent measure on that sample\,
and the risk measure diverges to minus infinity. This instability was fi
rst discovered on the special example of Expected Shortfall which is used
here both as an illustration and as a springboard for generalization.\n\n/
/indico.ictp.it/event/a08129/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08129/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Two-state model for two
different molecular motors: Monomeric helicase and KIF1A"
DTSTART;VALUE=DATE-TIME:20080626T100000Z
DTEND;VALUE=DATE-TIME:20080626T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08134@ictp.it
DESCRIPTION:Biological molecular motors are the enzymes which play crucial
roles in different cellular and developmental processes in a living cell
.\n Helicases are molecular motors that unwind double-stranded nucleic aci
ds such as DNA and RNA. KIF1A is a single headed kinesin motor that takes
part in intracellular transport along microtubule from cell center to cel
l periphery. They both perform mechanical work by hydrolyzing ATP.\nIn t
he flashing ratchet picture\, the motor proteins switch between two state
s: one where the motor is tightly bound to the track and another where th
e motor is weakly bound and can diffuse along the track. This flashing r
atchet mechanism can be found in these two motors. In this talk I will di
scuss the speed of unwinding of the double stranded nucleic acid and fluct
uations around the average unwinding velocity of the monomeric helicase.
Then I will emphasize the effects of mechanochemistry and steric interact
ions on the KIF1A traffic.\n\n//indico.ictp.it/event/a08134/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08134/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Statistical physics in f
racture"
DTSTART;VALUE=DATE-TIME:20080703T100000Z
DTEND;VALUE=DATE-TIME:20080703T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08200@ictp.it
DESCRIPTION:In this talk I review two current problems where statistical m
echanics and fracture meet (see Adv. Phys. 55\, 349 (2006). The first is
the so-called size effect\, which measures the strength of a sample as a f
unction of its size. This can be addressed both in the traditional FSS se
nse - becoming an extremal statistics problem - and in the presence of one
defect\, a notch (Phys. Rev. Lett. 100\, 055502 (2008)). I present some
recent results on the application of scaling theory and extensive simulat
ions of simple fracture models to illustrate the fundamental role of disor
der here. The second problem is the creep of a fracture line. I discuss e
xperiments done at HUT using the so-called peel-in-nip geometry to split p
aper in two (Phys. Rev. Lett. 99\, 145504 (2007)) in the creep setup\, or
under a constant external force. The scenario can be used to test fundame
ntal results in the theory of elastic manifolds in random media\, in parti
cular the depinning of lines with long-range elasticity. Listening to the
dynamics via acoustic emission measurements allows to look at the tempora
l dynamics with high accuracy.\n\n//indico.ictp.it/event/a08200/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08200/
END:VEVENT
BEGIN:VEVENT
SUMMARY:INFORMAL SEMINAR on Statistical Physics: " Who is keeping you in
that community? "
DTSTART;VALUE=DATE-TIME:20080717T100000Z
DTEND;VALUE=DATE-TIME:20080717T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08210@ictp.it
DESCRIPTION:It is a common experience that groups of people with tight int
er-relations can be easily formed or dissolved. These groups are not howev
er restricted to social environments\; they can be found in systems rangin
g from protein interaction networks to the Web and can be seen as manifest
ations of complexity. Within the framework of graph theory such groups are
known as clusters or communities and many techniques have been proposed t
o detect them.\n\nIn this talk I will show that a recently introduced infe
rence method on networks is able not only to determine clusters but also t
o measure the extent to which each element influences the group membership
of its neighbors. We demonstrate the generality and relevance of this inf
ormation-based hierarchy with several real-world examples. This is joint w
ork with Jose Javier Ramasco of ISI Torino.\n\n//indico.ictp.it/event/a082
10/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08210/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Role of ini
tial conditions in ageing of quenched systems"\n
DTSTART;VALUE=DATE-TIME:20080724T100000Z
DTEND;VALUE=DATE-TIME:20080724T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08212@ictp.it
DESCRIPTION:Ageing phenomenon is observed in slowly relaxing nonequilibriu
m systems.\nExamples not only include complex glassy systems\, but also si
mple statistical mechanics systems when rapidly quenched in temperature.
These quenched systems usually show scaling properties and universal behav
iour while ageing I shall discuss some of these out-of-equilibrium propert
ies in an exactly solvable example\, long-range spherical model\, and show
how the ageing classes depend on classes of initial conditions.\n\n//indi
co.ictp.it/event/a08212/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08212/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SEMINAR on\n\nDisorder and strong electron correlations: "Role of
initial conditions in \nageing of quenched systems"\n\n
DTSTART;VALUE=DATE-TIME:20080730T050000Z
DTEND;VALUE=DATE-TIME:20080730T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08216@ictp.it
DESCRIPTION:Ageing phenomenon is observed in slowly relaxing nonequilibriu
m systems.\nExamples not only include complex glassy systems\, but also si
mple statistical mechanics systems when rapidly quenched in temperature.
These quenched systems usually show scaling properties and universal behav
iour while ageing I shall discuss some of these out-of-equilibrium propert
ies in an exactly solvable example\, long-range spherical model\, and show
how the ageing classes depend on classes of initial conditions.\n\n//indi
co.ictp.it/event/a08216/
LOCATION:SISSA - Lecture Room D
URL://indico.ictp.it/event/a08216/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"The statist
ics of the work done in a quantum quench"\n
DTSTART;VALUE=DATE-TIME:20080925T100000Z
DTEND;VALUE=DATE-TIME:20080925T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08239@ictp.it
DESCRIPTION:A quantum quench is a rapid change in time of a control parame
ter in the hamiltonian describing a quantum\, correlated many body system.
The physics of this paradigmatic nonequilibrium process\, which has been
realized recently in the context of cold atoms\, is of particular interes
t in quantum critical systems. In this talk I will discuss a fundamental w
ay to characterize these processes using basic thermodynamic variables and
looking at their statistics. Focusing on the statistics of\nthe work done
in a quantum quench I will first elucidate the relation between the proba
bility distribution of the work\, quantum Jarzynski equalities\, and the L
oschmidt echo\, a quantity that emerges usually in the context of dephasin
g. Using this connection\, I will then characterize the statistics of the
work done on a quantum Ising chain by quenching locally\nor globally the t
ransverse field\, showing that for local quenches starting at criticality\
, the probability distribution of the work displays an interesting edge si
ngularity.\n\nRef: Alessandro Silva\, Phys. Rev. Lett. 101\, 120603 (2008)
.\n\n//indico.ictp.it/event/a08239/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08239/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Super-insu
lator: What is it?"
DTSTART;VALUE=DATE-TIME:20081002T100000Z
DTEND;VALUE=DATE-TIME:20081002T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08243@ictp.it
DESCRIPTION:We analyze the recent experiments in InO films which show a dr
amatic jump in the resistance as a function of the applied voltage. These
experiments provoke speculations about a "super-insulator" as a "new stat
e of matter". We show that all the qualitative details of recent experime
nts and many\nquantitative estimations follow from the model that assumes
lack of equilibrium between electron system and phonon bath which arises
at low enough temperatures at a finite voltage bias.\n\n//indico.ictp.it/e
vent/a08243/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08243/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar: "Density Functional and
Dynamical Mean-Field Theory (DFT+DMFT) method and its applications to cor
relation effects in electronic structure of real materials"
DTSTART;VALUE=DATE-TIME:20081008T150000Z
DTEND;VALUE=DATE-TIME:20081008T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08250@ictp.it
DESCRIPTION:Dynamical Mean-Field Theory (DMFT) is a powerful tool to study
Coulomb correlations. To use it for real materials it should be combined
with Density Functional Theory (DFT) methods. Wannier functions are used a
s localized orbitals basis to define Hamiltonian parameters. Coulomb inter
action parameters are obtained in “constrained DFT” calculations.\nDFT
+DMFT method was applied to a number of narrow-band materials where correl
ation effects result in anomalous physical properties:\n- Strongly correla
ted metals SrVO3 \n- Metal-insulator transition in V2O3\n- Heavy fermions
in d-system Li2VO4\n- Charge transfer insulator NiO\n- Metal insulator tra
nsition with pressure in MnO \n- Correlated covalent insulators FeSi and
FeSb2\n- Novel superconductor LaOFeAs\n- Jahn-Teller distortions in KCuF3\
n- f-electrons localization in Ce\n\n//indico.ictp.it/event/a08250/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08250/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:\n"Ab initio
electronic structure\, \nballistic conductance\, and magnetism of \ntransi
tion metal nanocontacts"\n
DTSTART;VALUE=DATE-TIME:20081009T100000Z
DTEND;VALUE=DATE-TIME:20081009T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08252@ictp.it
DESCRIPTION:Metallic nanocontacts consisting of just a single monatomic wi
re (atomic chain) connecting two macroscopic electrodes can be now fabrica
ted\, imaged\, and explored by means of various techniques such as scannin
g tunneling microscopy or mechanically controllable break junctions. We pr
esent the first principles density functional theory study of such nanowi
re contacts making a special emphasis on the interplay between their magn
etic and electron transport properties. We show the results for ferromagne
tic Ni nanocontacts and for Pt nanocontacts where the one-dimensional mon
atomic wires (unlike to the bulk) were recently shown to develop magnetism
.\n\n//indico.ictp.it/event/a08252/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08252/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Subtle prob
lems of one-dimensional localization: Devil's staircase of statistical a
nomalies "\n
DTSTART;VALUE=DATE-TIME:20081016T100000Z
DTEND;VALUE=DATE-TIME:20081016T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08254@ictp.it
DESCRIPTION:It is shown that in the old and celebrated problem of one-dime
nsional localization on a lattice with random on-site energies the joint p
robability distribution (JPD) of amplitudes and phases of random eigenfunc
tion exhibits an anomaly at any rational filling factor. The principal ano
maly at half-filling is described by the transfer-matrix equation with the
two-dimensional (amplitude and phase) internal space and an explicit depe
ndence on both co-ordinates. We show that the zero mode variant of this e
quation is exactly solvable and find the unique solution for the JPD.\n\n/
/indico.ictp.it/event/a08254/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08254/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:\n"Real-time
diagrammatic Monte Carlo for nonequilibrium quantum transport"
DTSTART;VALUE=DATE-TIME:20081022T100000Z
DTEND;VALUE=DATE-TIME:20081022T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08258@ictp.it
DESCRIPTION:We propose a novel approach to nonequilibrium real-time dynami
cs of quantum impurities models coupled to biased non-interacting leads\,
such as those relevant to quantum transport in nanoscale molecular devices
. The method is based on a Diagrammatic Monte Carlo sampling of the real-
time perturbation theory along the Keldysh contour. We benchmark the metho
d on a non-interacting resonant level model and\, as a first non-trivial a
pplication\, we study zero temperature non-equilibrium transport through a
vibrating molecule.\n\n//indico.ictp.it/event/a08258/
LOCATION:ICTP
URL://indico.ictp.it/event/a08258/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"Non-equilib
rium Luttinger liquid: Zero-bias anomaly and dephasing"\n
DTSTART;VALUE=DATE-TIME:20081106T100000Z
DTEND;VALUE=DATE-TIME:20081106T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08260@ictp.it
DESCRIPTION:A one-dimensional system of interacting electrons out of equil
ibrium is studied in the framework of the Luttinger liquid model. We analy
ze several setups and develop a theory of tunneling into such systems. A
remarkable property of the problem is the absence of relaxation in energy
distribution functions of left- and right-movers\, yet the presence of the
finite dephasing rate due to electron-electron scattering\, which smears
zero-bias-anomaly singularities in the tunneling density.\n\n//indico.ictp
.it/event/a08260/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08260/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Dissipative
dynamics in almost integrable system or life-time of dark solitons"\n
DTSTART;VALUE=DATE-TIME:20081113T100000Z
DTEND;VALUE=DATE-TIME:20081113T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08270@ictp.it
DESCRIPTION:The exact quantum excitations of weakly interacting one dimens
ional Bose gas can be observed by their semi-classical counterpart\, a dar
k soliton. Dark solitons are protected from decay by integrability and ha
ve infinite lifetime. In this talk I shall discuss possible source of no
n-integrability in realistic systems and show how solitons acquire a finit
e life-time.\n\n//indico.ictp.it/event/a08270/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08270/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Inference of effect
ive interactions between retinal neurons"\n
DTSTART;VALUE=DATE-TIME:20081118T113000Z
DTEND;VALUE=DATE-TIME:20081118T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08268@ictp.it
DESCRIPTION:Multi-electrodes techniques allow to register the simultaneous
activity of tens of ganglion cells in the vertebrate retina for several h
ours. Recently a low-dimensional representation of this activity was prop
osed\, based on the notion of effective interactions. I will present how t
hese couplings can be efficiently inferred in two models (Ising and Integr
ate-and-Fire). The dependence of the interactions on the visual stimulus\,
and their spatial structure will be discussed.\n\n//indico.ictp.it/event/
a08268/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08268/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Topological
objects in two-gap superconductor"\n
DTSTART;VALUE=DATE-TIME:20081120T100000Z
DTEND;VALUE=DATE-TIME:20081120T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08272@ictp.it
DESCRIPTION:We discuss topological objects\, in particular the non-Abrikos
ov vortex and the magnetic knot made of the twisted non-Abrikosov vortex\,
in two-gap superconductor. We show that there are two types of non-Abrik
osov vortex in Ginzburg-Landau theory of two-gap superconductor\, the D-ty
pe which has no concentration of the condensate at the core and the N-type
which has a non-trivial profile of the condensate at the core\, under a w
ide class of realistic interaction potential. Furthermore\, with the Josep
hson interaction we get the vortex molecule which is different from the ax
isymmetric vortex.\n\n//indico.ictp.it/event/a08272/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08272/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: " Braid construction
for low-leakage topological quantum computation "\n
DTSTART;VALUE=DATE-TIME:20081124T113000Z
DTEND;VALUE=DATE-TIME:20081124T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08275@ictp.it
DESCRIPTION:A topological quantum computer encodes quantum information in
a topologically protected Hilbert space of non-Abelian anyons. Braiding no
n-Abelian anyons in space-time leads to robust quantum information process
ing. In this talk\, I will first give a brief overview of the emergence an
d braiding of anyons in fractional quantum Hall systems. Then\, I will use
Fibonacci anyons to discuss braid (or quantum gate) construction toward u
niversal topological quantum computation\, with focus on avoiding leakage
errors in braid construction. Such considerations result in high-accuracy
low-leakage quantum gates for topological quantum computation.\n\n//indico
.ictp.it/event/a08275/
LOCATION:Lecture Room 'D'\, SISSA Bldg.
URL://indico.ictp.it/event/a08275/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Interplay b
etween Kondo effect and Rashba precession in magnetic field"\n
DTSTART;VALUE=DATE-TIME:20081127T100000Z
DTEND;VALUE=DATE-TIME:20081127T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08277@ictp.it
DESCRIPTION:The influence of Thomas-Rashba (TR) precession on the Kondo tu
nneling through quantum dots is discussed. It is shown that this precessi
on is pertinent only at finite magnetic fields. TR precession results in
peculiar anisotropy of effective g-factor and initiates dephasing of Kondo
tunneling at low temperature\, which strongly depends on the magnitude an
d direction of magnetic field.\n\n//indico.ictp.it/event/a08277/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08277/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Spectra of sparse r
andom matrices and localization on random graphs"\n
DTSTART;VALUE=DATE-TIME:20081202T113000Z
DTEND;VALUE=DATE-TIME:20081202T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08278@ictp.it
DESCRIPTION:We compute the spectral density for ensembles of sparse symmet
ric random matrices using replica. Our formulation of the replica-symmetri
c ansatz shares the symmetries of the one suggested in a seminal paper by
Rodgers and Bray (symmetry with respect to permutation of replica / and/ r
otation symmetry in the space of replica)\, but uses a different represent
ation in terms of superpositions of Gaussians. It gives rise to a pair of
integral equations which can be solved by a stochastic population-dynamics
algorithm. Remarkably our representation allows to identify pure-point co
ntributions to the spectral density related to the existence of normalizab
le eigenstates. Our approach is not restricted to matrices defined on grap
hs with Poissonian degree distribution. Matrices defined on regular random
graphs or on scale-free graphs\, are easily handled. We also look at matr
ices with row constraints such as discrete graph Laplacians\, and at Rando
m Schroedinger Operators defined on random graphs. Our approach naturally
allows to unfold the total density of states into contributions coming fr
om vertices of different local coordination and an example of such an unfo
lding is presented. Our results are well corroborated by numerical diagona
lization studies of large finite random matrices.\n\n//indico.ictp.it/even
t/a08278/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08278/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"Nonequilibr
ium kinetics of a disordered Luttinger liquid"\n
DTSTART;VALUE=DATE-TIME:20081204T100000Z
DTEND;VALUE=DATE-TIME:20081204T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08279@ictp.it
DESCRIPTION:We develop a kinetic theory for strongly correlated one-dimens
ional electron systems out of equilibrium\, within the framework of the L
uttinger liquid model. In the absence of disorder (backscattering off imp
urities)\, the model is completely integrable and as such exhibits no rel
axation to equilibrium. We formulate a theoretical framework to study rel
axation processes due to the interplay of disorder and electron-electron i
nteractions\, based on kinetic equations for electron and plasmon distribu
tion functions. We calculate the rate of energy relaxation (equilibration)
in a disordered Luttinger liquid\, relevant to the transport properties o
f quantum wires at finite bias voltage. Remarkably\, for not too low tempe
rature and bias\, the energy-relaxation rate is found to be given by the r
ate of elastic scattering off disorder\, independent of the strength of e
lectron-electron interaction and temperature.\n\n//indico.ictp.it/event/a0
8279/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08279/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Phase transitions i
n the quantum conductance problem"\n
DTSTART;VALUE=DATE-TIME:20081209T113000Z
DTEND;VALUE=DATE-TIME:20081209T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08280@ictp.it
DESCRIPTION:Linear statistics on ensembles of random matrices occur freque
ntly in many applications. We present a general method to compute probabil
ity distributions of linear statistics for large matrix size N. This is\na
pplied to the calculation of conductance and shot noise for ballistic scat
tering in chaotic cavities\, in the limit of large number of open channels
. The method is based on a mapping to a Coulomb gas problem in Laplace spa
ce\, displaying phase transitions as the Laplace parameter is varied. As a
consequence\, the sough distribution displays a central Gaussian region f
lanked on both sides by non-Gaussian tails\, and weak non-analytical point
s at the junction of the two regimes.\n\n//indico.ictp.it/event/a08280/
LOCATION:SISSA Main Bldg\, Lecture Room 'D'
URL://indico.ictp.it/event/a08280/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:\n"Transport
through superconducting junction of multiple one-dimensional quantum wires
"
DTSTART;VALUE=DATE-TIME:20081211T100000Z
DTEND;VALUE=DATE-TIME:20081211T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08282@ictp.it
DESCRIPTION:We investigate transport properties of a superconducting junct
ion of one-dimensional quantum wires. We include the effect of electron-el
ectron interaction within the one-dimensional quantum wires using a weak i
nteraction renormalization group (WIRG) procedure. Due to the proximity ef
fect\, transport across the junction occurs via direct tunneling as well a
s via crossed Andreev channel. We find that the fixed point structure of t
his system is far more rich than the fixed point structure of a normal met
al-superconductor (NS) junction\, where we only have two fixed points - th
e fully insulating fixed point or the Andreev fixed point. Even a two wire
system with a superconducting junction i.e. a normal metal-superconductor
-normal metal (NSN) structure\, has non-trivial fixed points with intermed
iate transmissions and reflections. We demonstrate possible scenarios for
production of pure spin current through such junctions and show that there
are fixed points in the theory which correspond to the case of pure spin
current. We have also shown that (a) effects due to inclusion of electron-
electron interaction induced back-scattering in the wire\, and (b) competi
tion between the charge transport via the electron and hole channels acros
s the junction give rise to a non-monotonic behavior of subgap conductance
as a function of temperature.\n\n//indico.ictp.it/event/a08282/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08282/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Quantum impurities
out-of-equilibrium"
DTSTART;VALUE=DATE-TIME:20081216T113000Z
DTEND;VALUE=DATE-TIME:20081216T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a08283@ictp.it
DESCRIPTION:We develop an exact non-perturbative framework to compute the
nonequilibrium steady state properties of quantum impurities connected to
leads subject to source-drain voltage. We show that in the open system li
mit the non-equilibrium physics is captured by eigenstates defined with bo
undary conditions set by the leads. The eigenstates are current carrying a
nd entropy producing\, with the dissipation inherent in the limit. We cons
truct these eigenstates by means of a recently introduced Scattering (or O
pen) Bethe Ansatz approach\, a generalization to nonequilibrium of the The
rmodynamic (or Closed) Bethe Ansatz. We compute the I(V) curve of the Int
eracting Resonance Level and observe a Fermi Edge Singularity out of equil
ibrium as the impurity level approaches resonance. We then apply the appro
ach to the quantum dot (the nonequilibrium Anderson Impurity model) and co
mpute the conductance G(V \; e_d)\, noting the formation of the Kondo peak
as the gate voltage e_d is decreased\, and the peak destruction as the so
urce-drain voltage V is increased.\n\n//indico.ictp.it/event/a08283/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a08283/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Algebraic propertie
s of Grassmann and Clifford subalgebras related to spanning hyperforests"\
n
DTSTART;VALUE=DATE-TIME:20090113T113000Z
DTEND;VALUE=DATE-TIME:20090113T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a092@ictp.it
DESCRIPTION:A supersymmetric theory with osp(1|2)-invariance can be used t
o describe spanning (hyper-)forests on a given graph. In a sigma-model\, t
he bosonic part of the superfield can be integrated out and the symmetry i
s realized\nnon-linearly in the remaining Grassmann degrees of freedom.\nW
e investigate the invariant osp(1|2) Grassmann and Clifford subalgebras. W
e discover that\, given an arbitrary vertex ordering\, a basis of independ
ent elements is given by terms labeled by non-crossing partitions\, respec
tively of the vertices of the graph\, and of a doubling of this set.\nThe
invariant Clifford subalgebra is isomorphic to a Temperley--Lieb Algebra\,
in a peculiar even/odd generalization.\nA relation involving four complex
fermions plays a central role in the construction\, and disentangles the
only 4-set crossing partition as a linear combination of the other partiti
ons with up to two blocks. This relation appears in different flavours\, a
nd equivalence of the formulations is shown.\n\n//indico.ictp.it/event/a09
2/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a092/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR:"Form factors in fini
te volume and finite temperature correlators"
DTSTART;VALUE=DATE-TIME:20090120T113000Z
DTEND;VALUE=DATE-TIME:20090120T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a097@ictp.it
DESCRIPTION:I review recent work related to the volume dependence of matri
x elements of local fields (form factors)\, giving a description valid to
all orders in inverse powers of the volume (i.e. only neglecting contribut
ions that decay exponentially with volume). This method can be used to tes
t exact solutions (derived using bootstrap methods in integrable models) a
gainst numerical data obtained by solving the field theory in a truncated
state space\; it is also useful in extracting matrix elements from numeric
al data such as those obtained from e.g. lattice field theory. Matrix elem
ents with disconnected pieces require special attention. Such matrix eleme
nts are important in computing finite temperature correlation functions. I
give a new method for generating a low temperature expansion\, which is e
valuated for the one-point function up to third order\, confirming a serie
s expansion conjectured by Leclair and Mussardo. Time permitting\, I also
briefly show how the results can be extended to a situation with boundarie
s.\n\n//indico.ictp.it/event/a097/
LOCATION:Lecture Room D-SISSA Main Building
URL://indico.ictp.it/event/a097/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: " Effective surface
tension and coarsening in models driven by interfacial noise "
DTSTART;VALUE=DATE-TIME:20090127T113000Z
DTEND;VALUE=DATE-TIME:20090127T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0911@ictp.it
DESCRIPTION:I review domain coarsening phenomena in the non-equilibrium dy
namics of discrete spin models with Z_2 symmetry. Standard classifications
distinguish between "curvature-driven" processes\, in which the interface
motion is driven by surface tension (e.g. Glauber dynamics)\, and purely
diffusive processes driven by multiplicative noise at the interfaces (e.g.
Voter model). There are evidences that slight changes of the microscopic
Voter-like rule (e.g. adding intermediate states) leads to the emergence o
f an effective surface tension. We explain this phenomenon deriving a macr
oscopic Langevin equation for these processes and studying it with field-t
heoretic and numerical methods.\n\n//indico.ictp.it/event/a0911/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0911/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Three body physics
with ultracold atoms: the Efimov effect and P-wave Feshbach resonances for
spin polarized fermions"
DTSTART;VALUE=DATE-TIME:20090203T113000Z
DTEND;VALUE=DATE-TIME:20090203T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0914@ictp.it
DESCRIPTION:In the first part of the talk I will very briefly review the b
asic facts about scattering theory in the S-wave and P-wave channel. I wil
l introduce the notions needed to describe low energy collisions in ultrac
old atoms: scattering amplitude\, scattering length\, scattering volume\,
true range and effective range of the interaction. I will then review the
Efimov effect for a bosonic system.\nThe main part of the talk will be dev
oted to the three-body problem for polarized fermions\, close to a P-wave
Feshbach resonance. I will present a two channel model useful to describe
the P-wave interaction. Through numerical and analytical solutions of the
model\, I obtain predictions for all the physical quantities relevant for
present experiments: low energy elastic and inelastic scattering propertie
s\, existence and lifetime of weakly bound trimers\, atom loss rate throug
h the three-body recombination mechanism. The model also excludes the pres
ence of an Efimov effect in the P-wave channel.\nApplications and future d
evelopments will conclude the talk.\n\n//indico.ictp.it/event/a0914/
LOCATION:Lecture Room D - SISSA Main Building
URL://indico.ictp.it/event/a0914/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "How to find a diffi
cult problem for a quantum computer"
DTSTART;VALUE=DATE-TIME:20090210T113000Z
DTEND;VALUE=DATE-TIME:20090210T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0917@ictp.it
DESCRIPTION:I will discuss generation of random instances of complete QMA
problems.\n\nThese are thought to be problems which are difficult to solve
even on a quantum computer. This will lead us to study a class of disorde
red Hamiltonians with some peculiar properties and to the hypothesis that
finding a difficult problem for a quantum computer might be a difficult ta
sk.\n\n//indico.ictp.it/event/a0917/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0917/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on on Disorder and strong electron correlations: " "Time e
volution of correlations in strongly interacting fermions and bosons"\n
DTSTART;VALUE=DATE-TIME:20090212T100000Z
DTEND;VALUE=DATE-TIME:20090212T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0918@ictp.it
DESCRIPTION:Using the adaptive time-dependent density matrix renormalizati
on group\, we study the time evolution of strongly correlated bosonic and
fermionic systems on one-dimensional lattices pushed out of equilibrium. I
n particular\, we investigate a system of interacting spinless fermions af
ter a sudden change in the interaction strength and a system of soft- core
bosons modeled by the Bose-Hubbard model released from a trapping box-pot
ential. By considering the momentum distribution function of the bosonic s
ystem\, we demonstrate the formation of (quasi-)coherent matter waves emer
ging from an initial Mott insulating state over a wide range of the intera
ction strength between the particles. In the fermionic system\, we find th
e density correlations to exhibit a characteristic light-cone-like time ev
olution which is representative of a ballistic transport of information. S
uch behavior is observed both\nwhen quenching an insulator into the metall
ic region and also when quenching within the insulating region\, but not
when a metallic state is quenched deep into the insulating regime. Instead
\, stable domain walls in the density correlations emerge during the time
evolution\, consistent with the predictions of the Kibble-Zurek mechanism.
\n\n//indico.ictp.it/event/a0918/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0918/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Relaxation dynamics
of isolated many-body systems"\n
DTSTART;VALUE=DATE-TIME:20090217T113000Z
DTEND;VALUE=DATE-TIME:20090217T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0921@ictp.it
DESCRIPTION:If an isolated quantum-mechanical many-body system is suddenly
forced out of thermal equilibrium\, does it relax to a new steady state o
r does it keep oscillating? How does the final state depend on the initia
l state? Recently it has become possible to investigate such fundamental
questions in experiments with ultracold atomic gases. Here we study two mo
dels of interacting fermions\, the Falicov-Kimball model in dynamical mean
-field theory [1] and a Hubbard chain with long-range hopping [2]. We obta
in the exact real-time dynamics after a sudden change of the Hubbard inter
action\, starting from a metallic or a Mott-insulating initial state. We o
bserve relaxation to a new steady state\, showing that the presence of the
Mott gap does not inhibit relaxation. The steady-state properties are des
cribed by generalized Gibbs ensembles which take all constants of motion i
nto account. We discuss under which conditions such ensembles provide the
correct statistical description of integrable systems [2].\n\n[1] M. Eckst
ein and M. Kollar\, Phys. Rev. Lett. 100\, 120404 (2008).\n[2] M. Kollar a
nd M. Eckstein\, Phys. Rev. A 78\, 013626 (2008).\n\n//indico.ictp.it/even
t/a0921/
LOCATION:Lecture Room D - SISSA Main Building
URL://indico.ictp.it/event/a0921/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter seminar: "Doping graphene with m
etal contacts"
DTSTART;VALUE=DATE-TIME:20090217T100000Z
DTEND;VALUE=DATE-TIME:20090217T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0922@ictp.it
DESCRIPTION:Measuring the transport of electrons through a graphene sheet
necessarily involves contacting it with metal electrodes. We study the ads
orption of graphene on metal substrates using first-principles calculation
s at the level of density functional theory. The bonding of graphene to A
l\, Ag\, Cu\, Au and Pt(111) surfaces is so weak that its unique "ultrarel
ativistic'' electronic structure is preserved. The interaction does\, howe
ver\, lead to a charge transfer that shifts the Fermi level by up to 0.5 e
V with respect to the conical points. The crossover from p-type to n-type
doping occurs for a metal with a work function ~5.4 eV\, a value much larg
er than the work function of free-standing graphene\, 4.5 eV. We develop
a simple analytical model that describes the Fermi level shift in graphene
in terms of the metal substrate work function. Graphene interacts with an
d binds more strongly to Co\, Ni\, Pd and Ti. This chemisorption involves
hybridization between graphene p_z-states and metal d-states that opens a
band gap in graphene. The graphene work function is as a result reduced co
nsiderably. In a current-in-plane device geometry this should lead to n-ty
pe doping of graphene.\n\n//indico.ictp.it/event/a0922/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0922/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Spin-torque
shot noise in magnetic tunnel junctions"\n\n
DTSTART;VALUE=DATE-TIME:20090219T100000Z
DTEND;VALUE=DATE-TIME:20090219T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0928@ictp.it
DESCRIPTION:A spin polarized current may transfer angular momentum to a fe
rromagnet\, resulting in a spin-torque phenomenon. At the same time the sh
ot noise\, associated with the current\, leads to a nonequilibrium stochas
tic force acting on the ferromagnet. We derive a stochastic version of the
Landau-Lifshitz-Gilbert equation for a magnetization of a "free" ferromag
netic layer in contact with a "fixed" ferromagnet. We solve the correspond
ing Fokker-Planck equation and show that the nonequilibrium noise yields t
o a nonmonotonic dependence of the precession spectrum linewidth on the cu
rrent.\n\n//indico.ictp.it/event/a0928/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0928/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Lanford Theorem and
the validity of Boltzmann equation"\n
DTSTART;VALUE=DATE-TIME:20090224T113000Z
DTEND;VALUE=DATE-TIME:20090224T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0929@ictp.it
DESCRIPTION:We will review the mathematical foundation of Boltzmann equati
on and the theorem of Lanford. \nWe will take particular care on the mathe
matical aspects of the theory.\n\n//indico.ictp.it/event/a0929/
LOCATION:Lecture Room D - SISSA Main Building
URL://indico.ictp.it/event/a0929/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SEMINAR on Disorder and strong electron correlations: "Multipartic
le interference in electronic Mach-Zehnder interferometers"\n
DTSTART;VALUE=DATE-TIME:20090226T100000Z
DTEND;VALUE=DATE-TIME:20090226T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0933@ictp.it
DESCRIPTION:Electronic Mach-Zehnder interferometers were constructed recen
tly from chiral one-dimensional integer quantum Hall edge states. These in
terferometers showed an unexpected behavior of the visibility of Aharonov-
Bohm (AB) oscillations in the nonlinear regime\, where the visibility deve
loped a lobe structure accompanied by the $pi$-jumps of the AB-phase [1].
We address these phenomena by studying the model of a Mach-Zehnder interfe
rometer\, where the one-dimensional electrons interact via long-range pote
ntial. We calculate exactly the visibility of the Aharonov-Bohm oscillatio
ns in this model\, which agrees well with experimental results.\n\n[1] "Un
expected Behavior in a Two-Path Electron Interferometer"\, I. Neder\, M. H
eiblum\, Y. Levinson\, D. Mahalu\, and V. Umansky\, Phys. Rev. Lett. 96\,
016804\, (2006)\n\n//indico.ictp.it/event/a0933/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0933/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Spreading processes in c
omplex techno-social networks"\n
DTSTART;VALUE=DATE-TIME:20090302T133000Z
DTEND;VALUE=DATE-TIME:20090302T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0937@ictp.it
DESCRIPTION:In different contexts we are challenged by multi-scale network
s where infrastructures composed by different technological layers are int
eroperating with the social component that drives their use and developmen
t. Examples are provided by the Internet\, the social Web\, the new WiFi c
ommunication technologies and transportation and mobility infrastructures.
The multi-scale nature and complexity of these techno-social networks are
crucial features in the understanding of these systems and the dynamical
processes occurring on top of them. We will discuss the central statistica
l features of these networks and their impact on epidemic\, contagion and
spreading processes in both the biological world and the ITC domain. We wi
ll present the development of realistic computational models based on the
network paradigm and the reaction–diffusion processes framework that all
ows their theoretical understanding. Finally we will analyze the central r
ole of complex networks thinking in the definition of predictive large sca
le computational approaches for the modeling of emergent disease spreading
.\n\n//indico.ictp.it/event/a0937/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a0937/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR:"Coarsening in 2d:exa
ct results\, simulations and experiments"\n\n\n\n
DTSTART;VALUE=DATE-TIME:20090303T113000Z
DTEND;VALUE=DATE-TIME:20090303T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0938@ictp.it
DESCRIPTION:Dynamical systems quenched from a disorder into an ordered pha
se\, may display coarsening phenomena. The simplest example is the Ising f
erromagnet. When the system is cooled rapidly through the transition tempe
rature\, domains of the two ordered phases form and grow (coarsen) with ti
me. In the present work we obtain the exact result for the statistics of t
he areas enclosed by domain boundaries for the coarsening dynamics of a no
nconserved scalar field in two dimensions. This result represents the firs
t analytical demostration of the dynamical scaling hypothesis for this sys
tem. These results can be also generalizated to the coarsening dynamics un
der the effect of finite temperature or the presence of quenched disorder.
All these results have been tested with simulations on the two-dimensiona
l square-lattice Ising model using a Montecarlo algorithm. We have also do
ne experiments on the coarsening dynamics of liquid crystals. It was propo
sed that deracemization in this system is a curvature-driven process. We t
est this prediction using our exact result for the distrubution of areas.
We demonstrate that deracemization in such liquid crystals belongs to the
Allen-Cahn universality class\, and that the exact formula\, can be used a
s a strict test for this dynamic universality class.\n\n//indico.ictp.it/e
vent/a0938/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0938/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar:"Phase diagram of a
Y-shaped Josephson junction network"\n
DTSTART;VALUE=DATE-TIME:20090310T113000Z
DTEND;VALUE=DATE-TIME:20090310T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0940@ictp.it
DESCRIPTION:It is shown that\, for pertinent values of the fabrication and
control parameters\, an attractive finite coupling fixed point emerges in
the phase diagram of a Y-junction of superconducting Josephson chains. T
he new fixed point arises only when the dimensionless flux f piercing the
central loop of the network equals \\pi. A detailed account of the Josep
hson current-phase relationship along the arms of the network\, near each
one of the allowed fixed points\, is provided. The results evidence remar
kable similarities between the phase diagram accessible to a Y-junction of
superconducting Josephson chains and the one found in the analysis.\n\n//
indico.ictp.it/event/a0940/
LOCATION:SISSA Main Bld. - Lecture Room 'D'
URL://indico.ictp.it/event/a0940/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar: "Signatures of the superfluid to \nMott insulato
r transition in cold bosonic atoms in 1D optical lattice"\n
DTSTART;VALUE=DATE-TIME:20090311T150000Z
DTEND;VALUE=DATE-TIME:20090311T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0942@ictp.it
DESCRIPTION:We study the Bose-Hubbard model using the finite size density
matrix renormalization group method. We obtain a complete phase diagram fo
r a system in the presence of a harmonic trap and compare it with that of
the homogeneous system.\nThe superfluid to the Mott insulator phase transi
tion is investigated using different experimental signatures of these phas
es in quantities such as momentum distribution\, visibility\, condensate f
raction and the total number of bosons at a particular density. The relati
onships between the various experimental signatures and the phase diagram
are highlighted.\n\n//indico.ictp.it/event/a0942/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0942/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Stretched q
uantum states emerging from Majorana zero modes"\n
DTSTART;VALUE=DATE-TIME:20090312T100000Z
DTEND;VALUE=DATE-TIME:20090312T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0941@ictp.it
DESCRIPTION:Effects associated with the existence of isolated zero modes o
f Majorana fermions are discussed. It is argued that the quantization of t
his system necessarily contains highly extended (stretched) quantum\nstate
s and that\, populating or depopulating such states by interacting with th
e quantum system\, leads to long- ranged teleportation-like processes. A
model consisting of a quantum wire embedded in a p-wave superconductor is
discussed as an explicit - and exactly solvable- example of a physical sys
tem with isolated Majorana zero modes.\n\n//indico.ictp.it/event/a0941/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0941/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Typical properties
of asset pricing theory in complex markets"
DTSTART;VALUE=DATE-TIME:20090317T113000Z
DTEND;VALUE=DATE-TIME:20090317T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0946@ictp.it
DESCRIPTION:The expansion in the diversity of instruments in financial mar
kets\, according to Asset Pricing Theory (APT)\, provides more means for r
isk diversification\, and brings the syetem closer to the limit of "comple
te markets"\, in which risk can be eliminated altogether.\nThe proliferati
on of credit derivatives in the past decade\, and the recent crisis\, have
raised serious doubts on this view\, mostly because of market imperfectio
ns\, i.e. deviations of real markets from the ideal conditions postulated
in APT.\nIn this talk\, I will first review the main insights of APT. Then
I will show that one can use the tools of statistical physics of disorder
ed systems to characterize the typical properties of a large random market
. This suggests that\, even in the idealized market described by APT\, the
proliferation of financial instruments erodes systemic stability and it d
rives the market to a critical state characterized by large susceptibility
.\n\n//indico.ictp.it/event/a0946/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0946/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: \n"Horizon i
n random matrix theory\, Hawking radiation and flow of cold atoms"\n\n
DTSTART;VALUE=DATE-TIME:20090319T100000Z
DTEND;VALUE=DATE-TIME:20090319T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0947@ictp.it
DESCRIPTION:We show that the large distance behavior of the density-densit
y correlation function of a weakly confined Random Matrix ensemble can be
exactly reproduced by a Gaussian scalar field theory in a curved two-dimen
sional space-time characterized by the presence of a singularity and of an
event horizon. Therefore\, we propose this as a low-energy effective theo
ry describing the ensemble\, in analogy to what has been done for other in
variant ensembles and Luttinger Liquid theory. The presence of an event ho
rizon in the curved space-time naturally gives rise to a the phenomenon kn
own as Hawking radiation. A similar mapping with another gravitational ana
logue model has been shown to exist with a Bose-Einstein condensate pushed
to flow at a velocity higher than its speed of sound. In this case the Ha
wking radiation is composed of sound waves propagating over the cold atoms
. Our work suggests a three-fold connection between a moving BEC system\,
black-hole physics and unconventional RMEs.\n\n//indico.ictp.it/event/a094
7/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0947/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Backward Fokker-Pla
nck Methods for First-Passage Problems"\n
DTSTART;VALUE=DATE-TIME:20090324T113000Z
DTEND;VALUE=DATE-TIME:20090324T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0949@ictp.it
DESCRIPTION:The Backward Fokker-Planck Equation (BFPE) provides an elegant
technique for solving a number of first-passage problems. After an introd
uction to the method\, the usefulness of the BFPE will be illustrated by a
pplying it\nto a number of problems of increasing complexity\, namely\n(i
) the simple random walk with an absorbing boundary at the origin\;\n(ii)
the simple random walk with an absorbing boundary moving with constant vel
ocity\;\n(iii) the simple random walk with two absorbing boundaries moving
at different velocities\, and\n(iv) the random walk in the presence of va
rious types of "shear flow" and an absorbing boundary at the origin.\nThe
last of these is a problem with very rich behavior\, depending on the natu
re of the "shear flow".\n\n//indico.ictp.it/event/a0949/
LOCATION:Lecture Room D - SISSA Main Building
URL://indico.ictp.it/event/a0949/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar: "Light-matter interactions for quantum informat
ion: Long-lived quantum memories"\n
DTSTART;VALUE=DATE-TIME:20090325T150000Z
DTEND;VALUE=DATE-TIME:20090325T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0953@ictp.it
DESCRIPTION:The ability to distribute and store quantum information would
provide the potential for revolutionary technological advances from comple
tely secure communication to quantum computing. Decoherence and propagati
on losses\, however\, severely limit our ability to implement these scheme
s. Quantum memories cannot be continuously read and refreshed as classical
memories can since any measurement will alter the underlying state. The
only option remaining is to isolate a memory from any external influences.
\nWe report recent implementations long-lived memories using collective ex
citations in atomic ensembles. Scattering of a light field from an ensembl
e results in the emission of a signal photon and an imprinted atomic spin
wave. By understanding the primary sources of the coherence\, magnetic fie
ld and atomic motion\, we show how one can combat their deleterious effect
s. We present an analysis of the dynamics of retrieval of information fro
m our memories and show how it was exploited to produce memory times in ex
cess of 6 milliseconds. We also demonstrate how one can use controlled in
teractions with magnetic fields to execute qubit rotations during storage.
The variation of retrieval dynamics with storage time can also be used as
a measure of initial populations of the atomic states.\n\n//indico.ictp.i
t/event/a0953/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0953/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Superfluid
turbulence at T=0"
DTSTART;VALUE=DATE-TIME:20090326T100000Z
DTEND;VALUE=DATE-TIME:20090326T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0954@ictp.it
DESCRIPTION:Superfluid turbulence (ST)\, also known as quantum turbulence\
, is a tangle of quantized vortex lines in a superfluid. ST can be create
d in a number of ways:\n(i) as a result of non-equilibrium kinetics of Bos
e-Einstein condensation\, in which case it is a manifestation of generic K
ibble-Zurek mechanism\,\n(ii) in the counter-flow of normal and superfluid
components\, \n(iii) as a result of macroscopic motion of a superfluid\,
in which case it can mimic (at large enough length scale) classical-fluid
turbulence.\n\nWe will make an introduction to the theory of relaxation ki
netics of superfluid turbulence at T=0. The physics of zero-temperature li
mit is very rich and attractive in view of essentially conservative charac
ter of vortex dynamics. The theory will allow us to interpret recent intri
guing experiments by A. Golov and collaborators.\n\n//indico.ictp.it/event
/a0954/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0954/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Extreme Eigenvalues
of Random Matrices"
DTSTART;VALUE=DATE-TIME:20090331T113000Z
DTEND;VALUE=DATE-TIME:20090331T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0957@ictp.it
DESCRIPTION:The statistical properties of the extreme (maximum/minimum) ei
genvalue of a random matrix are of interest in diverse fields ranging from
disordered systems to statistical data analysis and even to string theory
. In this talk I'll discuss some recent developments on the theory of extr
emely rare fluctuations of the largest eigenvalue and its various applicat
ions.\n\n//indico.ictp.it/event/a0957/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0957/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Symmetry ca
uses a huge conductance peak in double quantum dots"\n\n
DTSTART;VALUE=DATE-TIME:20090402T100000Z
DTEND;VALUE=DATE-TIME:20090402T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0963@ictp.it
DESCRIPTION:We predict a huge interference effect contributing to the cond
uctance through large ultra-clean quantum dots of chaotic shape. When a do
uble-dot structure is made such that the dots are the mirror-image of each
other\, constructive interference can make a tunnel barrier located on th
e symmetry axis effectively transparent. We show (via theoretical analysis
and numerical simulation) that this effect can be orders of magnitude lar
ger than the well-known universal conductance fluctuations and weak-locali
zation (both less than a conductance quantum). A small magnetic field dest
roys the effect\, massively reducing the double-dot conductance\; thus a m
agnetic field detector is obtained\, with a similar sensitivity to a SQUID
\, but requiring no superconductors.\n\n[Robert S. Whitney\, P. Marconcini
\, M. Macucci\, to appear in Phys. Rev. Lett. (2009) arXiv:0902.3099]\n\n/
/indico.ictp.it/event/a0963/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0963/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Fibonacci Anyons an
d Topological Quantum Computation"
DTSTART;VALUE=DATE-TIME:20090407T113000Z
DTEND;VALUE=DATE-TIME:20090407T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0965@ictp.it
DESCRIPTION:Topological quantum computation is considered the best proposa
l to overcome local errors in the realization of a quantum computer. In th
is scheme\, it is well known that Fibonacci anyons can be used to implemen
t the universal quantum computation\, allowing to approximate with their b
raidings every single-qubit and two-qubit gate at any given accuracy. In t
his talk we will analyze the key features of these non-abelian anyons and
of their braiding group\; we will study the main technics used to achieve
the compiling of single-qubit gates\, focusing our attention on Bonesteel'
s "brute force" approach and on the quantum hashing through the icosahedra
l group.\n\n//indico.ictp.it/event/a0965/
LOCATION:Lecture Room D - SISSA Main Building
URL://indico.ictp.it/event/a0965/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA CONDENSED MATTER SEMINARS: "Re-Visiting Orbital D
iamagnetism: A Surprise"
DTSTART;VALUE=DATE-TIME:20090415T150000Z
DTEND;VALUE=DATE-TIME:20090415T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0968@ictp.it
DESCRIPTION:It is generally known that the orbital diamagnetism of a clas
sical system of charged particles in thermal equilibrium is identically ze
ro - the Bohr-van Leeuwen theorem. Physically\, this null result derives f
rom the exact cancellation of the orbital diamagnetic moment associated wi
th the complete cyclotron orbits of the charged particles by the paramagne
tic moment subtended by the incomplete orbits skipping the boundary in the
opposite sense. Motivated by this crucial\, but subtle role of the bounda
ry\, wed have simulated here the case of a finite but unbounded system\, n
amely that of a charged particle moving on the surface of a sphere in the
presence of an externally applied uniform magnetic field. Following a real
space-time approach based on the classical Langevin equation\, we have co
mputed the orbital magnetic moment which now indeed turns out to be non-ze
ro\, and has the diamagnetic sign. To the best of our knowledge\, this is
the first report of the possibility of finite classical diamagnetism in pr
inciple\, and it is due to the avoided cancellation\n\n//indico.ictp.it/ev
ent/a0968/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0968/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SEMINAR on Disorder and strong electron correlations:" Local densi
ty of states of 1D Mott insulators and CDW states with a boundary "\n\n
DTSTART;VALUE=DATE-TIME:20090416T100000Z
DTEND;VALUE=DATE-TIME:20090416T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0969@ictp.it
DESCRIPTION:We determine the local density of states (LDOS) of one-dimensi
onal incommensurate charge density wave (CDW) states in the presence of a
strong impurity potential\, which is modeled by a boundary. We find that t
he CDW gets pinned at the impurity\, which results in a singularity in the
Fourier transform of the LDOS at momentum 2k_F. At energies above the spi
n gap we observe dispersing features associated with the spin and charge d
egrees of freedom respectively. In the presence of an impurity magnetic fi
eld we observe the formation of a bound state localized at the impurity. A
ll of our results carry over to the case of 1D Mott insulators by exchang
ing the roles of spin and charge degrees of freedom. We discuss the impli
cations of our result for scanning tunneling microscopy experiments on spi
n-gap systems such as two-leg ladder cuprates.\n\n//indico.ictp.it/event/a
0969/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0969/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar: "Spin quantum Hall effect in class C supercondu
ctors and quantum spin Hall effect in graphene"\n
DTSTART;VALUE=DATE-TIME:20090420T100000Z
DTEND;VALUE=DATE-TIME:20090420T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0970@ictp.it
DESCRIPTION:We study a delocalization transition in a system of noninterac
ting quasiparticles moving in two dimensions\, which belongs to a new symm
etry class C. This symmetry class can be realized in a dirty\, gapless su
perconductor in which time-reversal symmetry for orbital motion is broken\
, but spin-rotation symmetry is intact. In this class spin current is tran
sferred by electron-hole pairs. Further\, we consider a three-dimensional
realization of class C. In the last part of the talk\, we discuss applica
tion of the generalized Chalker-Coddington network model to the quantum sp
in Hall effect in graphene\, which differs significantly from class C. In
particular\, spin current is transferred by electrons with opposite spins
moving in the opposite directions.\n\n//indico.ictp.it/event/a0970/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0970/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Generating Function
al Analysis of an Interacting Geometric Brownian Motion for Stock Market D
ynamics "\n
DTSTART;VALUE=DATE-TIME:20090421T113000Z
DTEND;VALUE=DATE-TIME:20090421T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0973@ictp.it
DESCRIPTION:In this talk I will discuss a minimal interacting generalisati
on of the geometric Brownian motion model be formally equivalent to a mode
l describing the dynamics of networks of analogue neurons. Using the Gener
ating Functional formalism\, I will show how one can solve for the steady
state solutions in a non-trivial and interesting regime\n\n//indico.ictp.i
t/event/a0973/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0973/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Trions and
quartet condensates in one-dimensional multicomponent \nultracold fermions
"\n
DTSTART;VALUE=DATE-TIME:20090423T100000Z
DTEND;VALUE=DATE-TIME:20090423T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0975@ictp.it
DESCRIPTION:In this talk\, we will discuss the possible stabilization of a
molecular superfluid phase in multicomponent attractive Fermi gas where m
ore than two fermions form a bound state. We will show\, by means of a low
-energy approach and large scale DMRG calculations\, that trionic (three-b
ody bound states) and quartet phases emerge in multicomponent ultracold fe
rmions loaded into one-dimensional optical lattice at sufficiently small
density.\n\n//indico.ictp.it/event/a0975/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0975/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Statistical Mechani
cs of sub-graph identification problems"\n
DTSTART;VALUE=DATE-TIME:20090428T113000Z
DTEND;VALUE=DATE-TIME:20090428T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0981@ictp.it
DESCRIPTION:Network analysis\, inference and optimization represent method
ological challenges which play a central role in large scale data analysis
. Their practical relevance arises from the huge quantity of empirical d
ata that is being made available in many fields of science\, biology and e
conomics in first place. In this talk we shall discuss some new statistic
al physics approaches to basic network optimization problems that come fro
m sub-graph identification.\nFirstly we show how to approach the so called
sub-graph isomorphism problem\, one of the most fundamental NP-hard probl
ems in graph theory. We display three applications: maximum clique identif
ication\, graph alignment and network motif counting. Secondly we discuss
how to generalize the cavity method to deal with the problem of searching
for sub-network which are subject to topological constraints. The specifi
c case of bounded depth Spanning trees is discussed in some detail\, toget
her with a novel application to high dimensional data clustering.\n\n//in
dico.ictp.it/event/a0981/
LOCATION:Lecture Room D - SISSA Main Building
URL://indico.ictp.it/event/a0981/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed matter seminar: "Stochastic approach to
chaotic stick-slip in granular systems"
DTSTART;VALUE=DATE-TIME:20090429T150000Z
DTEND;VALUE=DATE-TIME:20090429T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0976@ictp.it
DESCRIPTION:The sliding of contacting surfaces is a formidable problem wit
h impact in many areas\, ranging from atomic to tectonic in scale. In seve
ral cases it can result in steady sliding or periodic stick-slip motion\,
but often displays an intermittent and erratic nature\, for which effectiv
e descriptions are lacking. In order to investigate this kind of dynamics
we have set up an experiment in which a rigid plate engages in stick-sli
p shear motion on a granular bed. In order to describe the resulting mot
ion we have adopted an unusual approach which is not deterministic in natu
re (as opposed to\, e.g. Burridge-Knopoff and Frenkel-Kontorova models)\,
finding that the dynamics can be accurately described in a quantitative wa
y by a simple stochastic equation\, in which the resulting force exerted
by the medium on the plate performs a random walk. Further work on the
statistical properties of friction in solid-on-solid systems and compariso
ns with other phenomena suggest that a large class of driven instabilities
can be described in terms of similar general mechanisms. Preliminary resu
lts on variable height and shaken granular bed are presented.\n\n//indico.
ictp.it/event/a0976/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0976/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Noise corr
elations in cold atoms"\n
DTSTART;VALUE=DATE-TIME:20090430T100000Z
DTEND;VALUE=DATE-TIME:20090430T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0982@ictp.it
DESCRIPTION:I explain a connection of so-called full distribution function
(an analogue of the full counting statistics)\, which we introduced and c
omputed (exactly in various cases!) with variety of exactly solvable model
s\, conformal field theory\, AdS/CFT and Langlands dualities.\n\n//indico.
ictp.it/event/a0982/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0982/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar: "Random matrix theory and \nits applications to t
he strong interactions"\n
DTSTART;VALUE=DATE-TIME:20090506T153000Z
DTEND;VALUE=DATE-TIME:20090506T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0988@ictp.it
DESCRIPTION:In this talk I review how the concept of Random Matrix Theory
(RMT) is used as an effective field theory of the theory of strong interac
tions in Quantum Chromodynamics (QCD). I begin by stating the approximati
ons made that map QCD to a sigma model - the theory of Goldstone modes - a
nd ultimately to a RMT formulation. Various correlation functions in the r
elevant symmetry class can be computed either from the sigma model or RMT\
, and then compared to numerical solutions of QCD in that limiting regime.
Recent developments include non-Hermitian RMT and complex eigenvalue spe
ctra of the QCD Dirac operator.\n\n//indico.ictp.it/event/a0988/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0988/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Commensura
te-incommensurate phase transition in electron systems"\n\n
DTSTART;VALUE=DATE-TIME:20090507T100000Z
DTEND;VALUE=DATE-TIME:20090507T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0986@ictp.it
DESCRIPTION:The talk will be on the influence of single electron bare spec
trum nonlinearity at the Fermi surface (curvature of the Fermi surface) on
the commensurate-incommensurate phase transition in 1D electron systems.\
n\n//indico.ictp.it/event/a0986/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0986/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter seminar: "What happens when Boso
ns are interacting\, confined and are at a finite temperature?"
DTSTART;VALUE=DATE-TIME:20090508T153000Z
DTEND;VALUE=DATE-TIME:20090508T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0987@ictp.it
DESCRIPTION:The successful observation of Bose-Einstein condensation (BEC)
in weakly interacting dilute alkali gases\, confined by inertial magneto-
optic traps\, has provoked a flood of activities both theoretically and ex
perimentally. By majority the ground state properties of interacting and c
onfined Bosons are studied with the stationary solutions of Gross-Pitaevsk
ii (GP) mean-field equation. In this talk as a contrast\, I shall present
a general microscopic theory of confined interacting Bosons at non-zero te
mperature. The method employed for this investigation is the double-time t
emperature Green function technique. I shall discuss some new results beyo
nd the usual mean-field theory and highlight the crucial role of temperatu
re\, confinement and interaction to the properties\; namely energetics and
depletion of the condensates. I shall also discuss the collective modes o
f the confined Bosons.\n\n//indico.ictp.it/event/a0987/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0987/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed matter seminar: "Band structure and mec
hanical properties of Titanium alloys"
DTSTART;VALUE=DATE-TIME:20090511T150000Z
DTEND;VALUE=DATE-TIME:20090511T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0991@ictp.it
DESCRIPTION://indico.ictp.it/event/a0991/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a0991/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Collective modes of
trapped Fermi gases with in-medium interaction"
DTSTART;VALUE=DATE-TIME:20090512T113000Z
DTEND;VALUE=DATE-TIME:20090512T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0990@ictp.it
DESCRIPTION:Due to the Pauli blocking of the intermediate states\, the sca
ttering matrix (or T matrix) of two fermionic atoms in a Fermi gas becomes
different from that of two atoms in free space. We calculate the in-medi
um T matrix in ladder approximation and study its effects on the propertie
s of the collective modes of a trapped gas in the normal-fluid phase. We i
ntroduce the in-medium interaction on both sides of the Boltzmann equation
\, namely in the calculation of the mean field and in the calculation of t
he collision rate. This allows us to explain the observed upward shift of
the frequency of the quadrupole mode in the collisionless regime. By inclu
ding the mean field\, we also improve considerably the agreement with the
measured temperature dependence of frequency and damping rate of the sciss
ors mode\, whereas the use of the in-medium cross section deteriorates the
description\, in agreement with previous work.\n\n//indico.ictp.it/event/
a0990/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0990/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Relativisti
c transport in clean graphene - a nearly perfect quantum liquid"\n
DTSTART;VALUE=DATE-TIME:20090514T100000Z
DTEND;VALUE=DATE-TIME:20090514T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0992@ictp.it
DESCRIPTION:The electrons and holes in a graphene sheet behave very much l
ike a relativistic liquid. As a consequence\, the properties of thermo-ele
ctric transport of this fluid of interacting Dirac fermions are rather pec
uliar. At small doping and high temperatures\, graphene exhibits many sig
natures of a quantum critical system: the inelastic scattering rate is set
only by the temperature\, and the conductivity assumes a nearly universal
value\, solely due to electron-hole friction. In this regime we find pro
nounced deviations from standard Fermi liquid behavior and a peculiar coll
ective cyclotron resonance in the frequency dependent response. Some of t
hese results have been anticipated by a relativistic hydrodynamic theory\,
and are fully confirmed by Boltzmann transport theory for weak coupling.
Most interestingly\, similar results are also found in the case of certai
n strong coupled liquids which can be solved exactly by the AdS-CFT corres
pondence. Moreover\, in that context it is interesting that undoped graph
ene turns out to be a nearly ideal fluid with an anomalously small electro
nic viscosity\, very similar to recent observations in the ultra-relativis
tic quark gluon plasma. I will also discuss possible consequences of the l
ow viscosity for electronic transport in clean graphene.\n\n//indico.ictp.
it/event/a0992/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0992/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Effective thermal d
ynamics following a quantum quench in a spin chain"\n\n
DTSTART;VALUE=DATE-TIME:20090519T113000Z
DTEND;VALUE=DATE-TIME:20090519T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0993@ictp.it
DESCRIPTION:Recent experiments with ultracold atomic gases have triggered
a great deal of interest in some fundamental aspects of the non-equilibriu
m dynamics of strongly correlated quantum systems. In particular\, they ra
ised an intense discussion on the general relation between system integrab
ility and thermalization in the long-time dynamics of such systems. \n\nIn
stead of focusing on the asymptotic values of significant observables\, we
take a rather different perspective and study the dependence of the intri
nsic dynamical time-scale on the initial state. We do this by considering
the quantum Ising chain: we drive it out-of-equilibrium by abruptly quench
ing the transverse field. We focus on the onsite autocorrelation function
of the order parameter\, extracting the phase coherence time from its asym
ptotic decay. This phase coherence time is shown to be determined only by
the final Hamiltonian gap\, and an effective temperature which depends on
the energy of the initial state after the quench. Moreover\, the dependenc
e of the coherence time on the effective temperature fairly agrees with th
at obtained in thermal equilibrium as a function of the equilibrium temper
ature. These results pertain to the Ising universality class\, while the i
ntegrability of the model seems not to be crucial.\n\n//indico.ictp.it/eve
nt/a0993/
LOCATION:SISSA Main Building - Room D
URL://indico.ictp.it/event/a0993/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Large devia
tions in non-equilibrium 1d systems"\n\n
DTSTART;VALUE=DATE-TIME:20090522T113000Z
DTEND;VALUE=DATE-TIME:20090522T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0994@ictp.it
DESCRIPTION:Interacting classical particles diffusing in 1d have provided
in recent years an interesting playground to study non-equilibrium phenome
na. The dynamics of some of these models is described by an evolution ope
rator\, which can be written as a spin chain Hamiltonian H. One is inter
ested in the steady state and in the probability that the system presents
an atypical current flow. These are described by large deviation function
s (ldf).\nFinding the ldf amounts to determining the ground state of H - a
task similar to the quantum problems. I will present different methods (
Bethe Ansatz\, fluctuating hydrodynamics) used to compute the ldf and to c
haracterize its singularities - which correspond to dynamical phase transi
tions. Some class of systems also present an intriguing duality between n
on-equilibrium and equilibrium\, that reveal for instance the origin of lo
ng-range correlations induced e.g. by contact with reservoirs of different
chemical potential.\n\n//indico.ictp.it/event/a0994/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a0994/
END:VEVENT
BEGIN:VEVENT
SUMMARY:CONDENSED MATTER AND STATISTICAL PHYSICS SECTION - SPECIAL SEMINAR
: "Learning from Bacteria about Information Processing"
DTSTART;VALUE=DATE-TIME:20090525T153000Z
DTEND;VALUE=DATE-TIME:20090525T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09100@ictp.it
DESCRIPTION:Bacteria\, the first and most fundamental of all organisms\, l
ead rich social life in complex hierarchical communities. Collectively\, t
hey gather information from the environment\, learn from past experience\,
and take decisions. Bacteria do not store genetically all the information
required for efficient responding to all possible environmental condition
s. To solve the new encountered problems (challenges) posed by the environ
ment\, they first asses the problem via collective sensing\, recall stored
information of past experience and then execute distributed information p
rocessing by the 109-12 bacteria using sophisticated communication strateg
ies to link the intracellular computation networks of each bacterium (incl
uding signaling path ways of billions of molecules) into a network of netw
orks. I will show illuminating movies of swarming intelligence of live bac
teria in which they solve optimization problems that are beyond what we\,
human being\, can solve with our most powerful computers. This will lead m
e to a discussion about the special nature of bacteria computational princ
iples.\n\n//indico.ictp.it/event/a09100/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09100/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Defect flows in con
formal minimal models"
DTSTART;VALUE=DATE-TIME:20090526T113000Z
DTEND;VALUE=DATE-TIME:20090526T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09103@ictp.it
DESCRIPTION:By a defect we mean a line of inhomogeneity where the expectat
ion values of fields are allowed to be discontinuous or even singular. Def
ects can also form an interface between two different theories. In the cas
e of conformal field theories those defects are especially interesting whi
ch are invariant under scale transformations. These conformal defects are
the fixed points of the renormalisation group flows. In the talk I will re
port a study of a simple example of a two-parameter space of renormalisati
on group flows with the aim of identifying new conformal defects in unitar
y minimal models.\n\n//indico.ictp.it/event/a09103/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09103/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter seminar: "Femtosecond time-resol
ved spectroscopy of the solid state"\n
DTSTART;VALUE=DATE-TIME:20090527T150000Z
DTEND;VALUE=DATE-TIME:20090527T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a0995@ictp.it
DESCRIPTION:Solids are characterized by their different degrees of freedom
charge\, lattice\, and spin. Coupling of these degrees of freedom to each
other results in fundamental phenomena like superconductivity (electron-p
honon coupling) or the Kondo effect (spin-dependent electron scattering).
Time-resolved spectroscopy employing femtosecond laser pulses faciliates d
irect and independent access of these degrees of freedom and occasionally
novel insight into coupling mechanisms. In this talk two examples will be
presented. (a) Quasi-one dimensional structurs form charge density waves.
Using time- and angle-resolved photoelectron spectroscopy we have succeede
d to monitor the single and many particle excitations in the charge densit
y wave compound TbTe_3 close to thermodynamic equilibrium. In case of more
intense optical excitation non-equilibrium conditions are generated\, whi
ch finally lead to melting of the charge density wave and facilitate an i
dentification of the responsible mode. (b) Electron injection from a metal
substrate into ice layers results in localization and subsequent stabiliz
ation of these excess electrons\, which occurs by electron-induced rearran
gement of water molecules. Due to the permanent electrical dipole moment t
his process is refered to as electron solvation and we find a pronounced c
orrelation of ice structure and solvation dynamics at such ice-metal inter
faces. Electron traps at crystalline ice surfaces\, which exhibit extremel
y long hot electron lifetimes up to minutes\, present a model system for s
pecfic reaction sites as demonstrated for electron induced dissociation of
Freon adsorbed on ice.\n\n//indico.ictp.it/event/a0995/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a0995/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"Nonlinear
dynamics of spin and charge in spin-Calogero model"\n
DTSTART;VALUE=DATE-TIME:20090528T100000Z
DTEND;VALUE=DATE-TIME:20090528T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09106@ictp.it
DESCRIPTION:The fully nonlinear dynamics of spin and charge in spin-Caloge
ro model is studied. The latter is an integrable one-dimensional model of
quantum spin-1/2 particles interacting through inverse-square interaction
and exchange. Classical hydrodynamic equations of motion are written for
this model in the regime where gradient corrections to the exact hydrodyn
amic formulation of the theory may be neglected. In this approximation va
riables separate in terms of dressed Fermi momenta of the model. Hydrody
namic equations reduce to a set of decoupled Riemann-Hopf (or inviscid Bur
gers') equations for the dressed Fermi momenta. We study the dynamics of
some non-equilibrium spin-charge configurations for times smaller than the
time-scale of the gradient catastrophe. We find an interesting interplay
between spin and charge degrees of freedom. In the limit of large coupli
ng constant the hydrodynamics reduces to the spin hydrodynamics of the Hal
dane-Shastry model.\n\n//indico.ictp.it/event/a09106/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09106/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Adiabatic dynamics
in a spin-1 chain with uniaxial single-spin anisotropy"\n
DTSTART;VALUE=DATE-TIME:20090609T110000Z
DTEND;VALUE=DATE-TIME:20090609T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09112@ictp.it
DESCRIPTION:We numerically study the adiabatic quantum dynamics of an anis
otropic spin-1 XY chain across a second order quantum phase transition. Th
e system is driven out of equilibrium by performing a quench on the uniaxi
al single-spin anisotropy\, that is supposed to vary linearly in time. We
focus on the behavior of the excess energy\, which quantifies the loss of
adiabaticity of the system during the evolution. For small system sizes on
ly the ground state and the first excited state effectively participate in
the evolution\, so the dynamics can be explained in terms of a Landau-Zen
er model\, which describes an avoided level crossing between two levels. F
or sufficiently large system sizes\, the excess energy after the quench ad
mits a non trivial scaling behavior that is not predictable by standard Ki
bble-Zurek arguments for isolated critical points or extended critical reg
ions. This emerges from a competing effect of many accessible low-lying ex
cited states\, inside the whole continuous line of critical points.\n\n//i
ndico.ictp.it/event/a09112/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09112/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR SPECIAL SEMINAR:\nPha
se transitions and random quantum satisfiability
DTSTART;VALUE=DATE-TIME:20090610T150000Z
DTEND;VALUE=DATE-TIME:20090610T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09116@ictp.it
DESCRIPTION:Alongside the effort underway to build quantum computers\, it
is important to better understand which classes of problems they will find
easy and which others even they will find intractable. Inspired by the su
ccess of the statistical study of classical constraint optimization proble
ms\, we study random ensembles of the QMA$_1$-\ncomplete quantum satisfiab
ility (QSAT) problem introduced by Bravyi.\nQSAT appropriately generalizes
the NP-complete classical\nsatisfiability (SAT) problem. We show that\, a
s the density of clauses/projectors is varied\, the ensembles exhibit quan
tum phase transitions between phases that are satisfiable and unsatisfiabl
e. Remarkably\, almost all instances of QSAT for any hypergraph exhibit th
e same\ndimension of the satisfying manifold. This establishes the random
QSAT decision problem as equivalent to a\, potentially new\, graph theoret
ic problem and that the hardest typical instances are likely to be localiz
ed in a bounded range of clause density.\n\nWork done in collaboration wit
h R. Moessner\, A. Scardicchio and S. Sondhi.\narXiv:0903.1904\n\n//indico
.ictp.it/event/a09116/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09116/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Dynamical processes
on scale-free networks: a mean field approach"\n
DTSTART;VALUE=DATE-TIME:20090616T113000Z
DTEND;VALUE=DATE-TIME:20090616T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09118@ictp.it
DESCRIPTION:We consider dynamical processes on scale-free networks. We in
troduce an approach allowing to derive Langevin equations for mean field o
rder parameters that implicitly account for degree heterogeneity. In parti
cular we focus on branching-annihilating random walks and we show that the
critical properties of such systems explicitly depend on the parameter ch
aracterizing the degree distribution. We also discuss the role of noise fo
r finite systems\, showing how heterogeneous topologies can strongly affec
t single realizations of the dynamical processes.\n\n//indico.ictp.it/even
t/a09118/
LOCATION:SISSA-Lecture Room D
URL://indico.ictp.it/event/a09118/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Acoustic Black Hole
s and the Correlations of Hawking Radiation"
DTSTART;VALUE=DATE-TIME:20090623T110000Z
DTEND;VALUE=DATE-TIME:20090623T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09119@ictp.it
DESCRIPTION:Hawking radiation in black holes is the most famous and elusiv
e prediction of Quantum Field Theory in curved spacetime\, but so far no e
xperiment is confirming its existence. More fundamental than the theory it
has been first derived\, Hawking radiation has been extended to any syste
m able to reproduce the geometrical features of a forming black hole spece
time: for example in supersonic flowing fluids the sound gets trapped exa
ctly as light in a black hole. Such supersonic flow configurations are cal
led "acoustic black holes" and can be used as laboratory to test gravitat
ional effects otherwise undetectable (as Hawking radiation). It has been r
ecently proposed how a clear signature of the presence of Hawking radiatio
n in acoustic black holes appears in the density correlation pattern\, ana
lytically obtained using the formal analogy between gravitation and hydrod
ynamics\, and numerically confirmed in an analysis able to take into accou
nt the full microscopic structure of the system. In this seminar the main
features of the analogy between gravitation and hydrodynamics are reviewed
. Then the peculiar correlation pattern associated to Hawking radiation is
showed\, and its important role to reveal it in near future experiments i
s underlined.\n\n//indico.ictp.it/event/a09119/
LOCATION:Lecture Room D - SISSA Main Building
URL://indico.ictp.it/event/a09119/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Horizon in Random M
atrix Theory\, Hawking Radiation and Flow of Cold Atoms"
DTSTART;VALUE=DATE-TIME:20090623T114500Z
DTEND;VALUE=DATE-TIME:20090623T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09120@ictp.it
DESCRIPTION:We show that the large distance behavior of the density-densit
y correlation function of a weakly confined Random Matrix ensemble can be
exactly reproduced by a Gaussian scalar field theory in a curved two-dimen
sional space-time characterized by the presence of a singularity and of an
event horizon. Therefore\, we propose this as a low-energy effective theo
ry describing the ensemble\, in analogy to what has been done for other in
variant ensembles and Luttinger Liquid theory. The presence of an event ho
rizon in the curved space-time naturally gives rise to a the phenomenon kn
own as Hawking radiation. A similar mapping with another gravitational ana
logue model has been shown to exist with a Bose-Einstein condensate pushed
to flow at a velocity higher than its speed of sound. In this case the Ha
wking radiation is composed of sound waves propagating over the cold atoms
. Our work suggests a three-fold connection between a moving BEC system\,
black-hole physics and unconventional RMEs.\n\n//indico.ictp.it/event/a091
20/
LOCATION:Lecture Room D - SISSA Main Building
URL://indico.ictp.it/event/a09120/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar: "Raman scattering in graphene: \nA window on ele
ctron dynamics"\n
DTSTART;VALUE=DATE-TIME:20090625T100000Z
DTEND;VALUE=DATE-TIME:20090625T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09122@ictp.it
DESCRIPTION:We will discuss Raman scattering in graphene. It turns out th
at the photoexcited electron-hole pairs\, which serve as intermediate stat
es in the process\, are long-lived and their dynamics can be described qua
siclassically. Moreover\, this dynamics can be probed in several experimen
ts.\n\n//indico.ictp.it/event/a09122/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09122/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Seminar: "Spontaneous ordering in Brownian dynami
cs: Some useful approaches"
DTSTART;VALUE=DATE-TIME:20090701T150000Z
DTEND;VALUE=DATE-TIME:20090701T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09126@ictp.it
DESCRIPTION:1. Phase transitions: combination of discrete and continues ap
proaches\; \n2. Temporal-spatial maps and “Wilson-camera” approach\; \
n3. “Object oriented” programming in cross-disciplinary modeling and "
exotic" interactions\; \n4. Reducing number of “particles”\; \n5. Chao
tic dynamics\, strange attractors\, solitary excitations and self-organize
d motion\; \n6. Random and controllable deposition and numerical potential
s to model friction\; \n7. Tribology\, directed transport and other studie
s made in TAU and BTU.\n\n//indico.ictp.it/event/a09126/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09126/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Analysis of isoheig
ht lines of rough surfaces using Schramm-Leowner evolution (SLE)"
DTSTART;VALUE=DATE-TIME:20090714T160000Z
DTEND;VALUE=DATE-TIME:20090714T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09189@ictp.it
DESCRIPTION:We investigate the statistics of isoheight lines of some rough
surfaces (simulated and grown) at different level sets around the mean h
eight in the saturation regime. We find that these contour lines are clos
ely related to Schramm-Leowner evolutions\, therefore suggesting that conf
ormal invariance is present.\nWe show that the isoheight lines on the WO3
surface are conformally invariant with the same statistics of domain walls
in the critical Ising model. They belong to the family of Schramm-Loewne
r evolutions with diffusivity coefficient of 3 (or SLE3). This can be reg
arded as the firstexperimental observation of SLE curves.\nWe also investi
gate the statistics of isoheight lines of 2+1 dimensional Kardar-Parisi-Zh
ang (KPZ) model. We find that the exponent describing the distribution of
the height-cluster size behaves differently for level cuts above and below
the mean height\, while the fractal dimensions of the height-clusters and
their perimeters remain unchanged. The statistics of the winding angle a
lso confirms this observation in particular that the contour lines of the
KPZ model lie in the same universality class as self-avoiding random walks
\, or SLE8/3.\n\n//indico.ictp.it/event/a09189/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a09189/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA CONDENSED MATTER SEMINARS: "Spin Hall Drag"
DTSTART;VALUE=DATE-TIME:20090909T150000Z
DTEND;VALUE=DATE-TIME:20090909T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09213@ictp.it
DESCRIPTION:Double-layer structures\, consisting of two parallel quantum w
ells separated by a potential barrier\, are an important class of nanosca
le electronic devices. Each layer hosts a quasi-two-dimensional electron
gas and electrons interact across the barrier via Coulomb interaction. The
combined action of the spin and pseudo-spin (associated with the layer i
ndex) degrees of freedom creates new phases in these bilayers where the s
pin and many-body interaction effects play a critical role. \n When an el
ectric current is driven in one (active) layer of the bi-layer\, the inter
-layer Coulomb interaction causes charge accumulation in the other (passi
ve) layer. This phenomenon\, known as Coulomb drag\, is of fundamental in
terest as a probe of electron correlations. Another effect of great intere
st is the Spin Hall Effect\, the generation of spin accumulation by an or
dinary electric current. The spin Hall effect is due to spin-orbit intera
ction and SOI and has been a subject of vigorous research both in semicon
ductors and metals in recent years not only because of its theoretical sub
tlety but also as a potential source of spin polarized currents.\n Lately
\, we have predicted and analyzed theoretically a new effect in bi-layers\
, which combines the interesting features of spin Hall effect and Coulomb
drag. We call it Spin Hall Drag. SHD consists in the generation of spin
accumulation across the passive layer by an electric current flowing along
the other layer. Besides being a striking example of an effect that depe
nds simultaneously on Coulomb interactions and spin-orbit coupling\, the
SHD has several unexpected and non-trivial features. It occurs in the abse
nce of a current in the passive layer and\, as we have shown\, it is pred
ominantly caused by a subtle effect known as side-jump in electron-electr
on collisions. This is at variance with the ordinary spin Hall effect\, w
hich\, for electrons in GaAs\, is dominated by an effect known as skew-sca
ttering. We have shown that the skew-scattering and the side-jump contrib
utions (considered for the first time in a context of electron- electron
scattering) are separated by different temperature dependences at low temp
erature T\, with the former vanishing much faster than the latter (T 3 vs
T 2). Our calculations indicate that the induced spin accumulation is la
rge enough to be detected in optical rotation experiments.\n\n//indico.ict
p.it/event/a09213/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09213/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar: "Modeling friction: Fro
m the nano- to macro-scales"
DTSTART;VALUE=DATE-TIME:20090916T150000Z
DTEND;VALUE=DATE-TIME:20090916T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09215@ictp.it
DESCRIPTION:Frictional motion plays a central role in diverse systems and
phenomena that span vast ranges of scales\, from the nanometer contacts in
herent in micro- and nanomachines and biological molecular motors to the g
eophysical scales characteristic for earthquakes. Despite the practical an
d fundamental importance of friction and the growing efforts in the field\
, many key aspects of dynamics of friction are still not well understood.
One of the main difficulties in understanding and predicting frictional re
sponse is the complexity of highly non-equilibrium processes going on in a
ny tribological contact which include detachment and re-attachment of mult
iple microscopic contacts (bonds) between the surfaces in relative motion
while still in contact. \nIn this lecture I will discuss microscopic model
s which establish relationships between the dynamics of formation and rupt
ure of individual contacts and frictional phenomena. First\, I will focus
on dynamics of nanoscale friction studied in friction force microscopy exp
eriments. In this case we found that experimentally observed velocity and
temperature dependencies of friction can be rationalized by explicitly co
nsidering the influence of temperature on the formation and rupturing of m
icroscopic contacts. Then\, dynamics of cracklike processes that occur a
t the interface between two macroscopic blocks prior to the onset of frict
ional motion will be discussed. In agreement with experimental observation
s\, the proposed model demonstrates that the onset of sliding is preceded
by well-defined detachment fronts initiated at the slider trailing edge an
d extended across the slider over limited lengths smaller than the overall
length of the slider. We found that three different types of detachment f
ronts may play a role in the onset of sliding: (i) Rayleigh (surface sound
) fronts\, (ii) slow detachment fronts\, and (iii) fast fronts. The import
ant consequence of the precursor dynamics is that before the transition to
overall sliding occurs\, the initially uniform\, unstressed slider is alr
eady transformed into a highly nonuniform\, stressed state. Our model allo
ws to explain experimental observations and predicts the effect of materia
l properties on dynamics of transition to sliding.\n\n//indico.ictp.it/eve
nt/a09215/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09215/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter seminar: "Master equation approa
ch to friction on a mesoscale"\n
DTSTART;VALUE=DATE-TIME:20090923T150000Z
DTEND;VALUE=DATE-TIME:20090923T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09214@ictp.it
DESCRIPTION:Kinetics of the earthquakelike model with a distribution of st
atic thresholds is reduced to a master equation which may be considered an
alytically. This approach naturally describes stick-slip and smooth slidi
ng regimes of tribological systems within a framework which separates the
calculation of the friction force from the studies of the properties of th
e contacts.\n\n//indico.ictp.it/event/a09214/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09214/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR - SPECIAL SEMINAR: "F
undamental nonlinear equations in physics\, and their fundamental solution
s"\n
DTSTART;VALUE=DATE-TIME:20090923T133000Z
DTEND;VALUE=DATE-TIME:20090923T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09222@ictp.it
DESCRIPTION:A brief overview of universal equations\, which govern the pro
pagation of nonlinear waves in various physical media (both classical - su
ch as optical fibers - and macroscopic quantum media\, such as Bose-Einste
n condensates\, BECs)\, will be given. The survey will include the nonline
ar Schroedinger (NLS)/Gross-Pitaevskii equations\, the sine-Gordon (SG) eq
uation\, the Korteweg - de Vries (KdV) equation\, the Kadomtsev - Petviash
vili (KP) equations\, and some others (the KP equations are two-dimensiona
l models). All the above-mentioned equations\, in their ideal form\, share
the fascinating property of the exact integrability\, by means of a mathe
matical technique known as "the inverse-scattering transform". Not only ar
e these equations ubiquitous and universal\, but also their fundamental so
lutions - first of all\, solitons\, i.e.\, solitary waves - play a profoun
dly important role in all physical settings to which the model equations a
pply. Solitons have been predicted in a great variety of physical systems\
, and one-dimensional solitons were observed and/or created experimentally
in nonlinear optics\, BEC\, long Josephson junctions (superconductivity)\
, fluid flows\, plasmas\, etc. A great challenge to the experiment is to p
roduce stable two- and three-dimensional solitons.\n\n//indico.ictp.it/eve
nt/a09222/
LOCATION:Lecture Room D - SISSA Main Building
URL://indico.ictp.it/event/a09222/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Universal
physics in quantum nonequilibrium processes: Quantum quenches\, work stati
stics and edge singularities"\n
DTSTART;VALUE=DATE-TIME:20091001T100000Z
DTEND;VALUE=DATE-TIME:20091001T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09225@ictp.it
DESCRIPTION:A quantum quench is a rapid change in time of a control parame
ter in the Hamiltonian describing a quantum\, correlated many-body system.
The physics of this paradigmatic non-equilibrium process\, which has bee
n realized recently in the context of cold atoms\, is of particular intere
st in quantum critical systems where concrete dynamical manifestations of
universality can be studied. In this talk I will discuss two fundamental
ways to characterize these processes\, by either looking at the statistics
of basic thermodynamic variables or at the asymptotics of correlators. I
will first elucidate the connection between a classic problem in condense
d matter physics\, the Fermi edge singularity\, the statistics of the wor
k done in a quantum quench\, and quantum Jarzynski equalities. Using thi
s connection\, I will discuss results for the statistics of the work in a
variety of systems\, such as the quantum Ising chain\, the Dicke model and
quantum impurities. I will show that quantum criticality manifests itsel
f in the emergence of interesting edge singularities in the statistics of
the work and discuss their universality. Similarly\, I will discuss how t
he critical properties are encoded in the asymptotics of non-equilibrium c
orrelators.\n\n//indico.ictp.it/event/a09225/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09225/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Phase-coher
ent transport in 2D topological insulators"\n
DTSTART;VALUE=DATE-TIME:20091008T100000Z
DTEND;VALUE=DATE-TIME:20091008T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09228@ictp.it
DESCRIPTION:We investigate an effective low energy theory of HgTe quantum
wells near their mass inversion thickness in a perpendicular magnetic fiel
d. By comparison of the effective band structure with a more elaborated a
nd well-established model\, the parameter regime and the validity of the e
ffective model are quantified. Optical transitions (between Landau levels
) in HgTe quantum wells are analyzed. We find selection rules which we fu
nctionalize to optically manipulate edge state transport. [1] In the abse
nce of magnetic fields\, the ballistic transport through HgTe quantum well
s in the so-called inverted regime is believed to be dominated by edge sta
te transport. The existence of these edge states (at zero magnetic field)
is one of the hallmarks of topological insulators. We show that transport
through the gapped bulk via evanescent modes can in general not be neglec
ted in ballistic HgTe quantum wells.\n\n[1] M.J. Schmidt\, E.G. Novik\, M.
Kindermann\, and B. Trauzettel\, Phys. Rev. B 79\, 241306(R) (2009)\n\n//
indico.ictp.it/event/a09228/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09228/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR:"Statistical mechanic
s of congestion"\n
DTSTART;VALUE=DATE-TIME:20091013T100000Z
DTEND;VALUE=DATE-TIME:20091013T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09229@ictp.it
DESCRIPTION:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR\n\n\n\nWithin the
framework of a simple model\, we are able to study the overall performanc
e of a given informational network\, depending on its uptaking as well as
on the level of traffic control. Simple enough to get analytical results\,
it still shows a very rich phenomenology\, presenting continuous\, disco
ntinuous as well as hybrid phase transitions between a free-flow phase and
a congested phase\, critical points and different scaling behaviors in th
e system size. We find that traffic control improves global performance\,
enlarging the free-flow region in parameter space only in heterogeneous ne
tworks. Traffic control introduces non-linear effects and\, beyond a criti
cal strength\, may trigger the appearance of a congested phase in a discon
tinuous manner. The model also reproduces the cross-over in the scaling of
traffic fluctuations empirically observed in the Internet.\nRef:\nPRE 79\
, 015101(R) (2009)\nJstat P08023 (2009)\n\n//indico.ictp.it/event/a09229/
LOCATION:Lecture Room D - SISSA Main Building
URL://indico.ictp.it/event/a09229/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:\n"Novel sup
erfluid states in bosonic systems"
DTSTART;VALUE=DATE-TIME:20091015T100000Z
DTEND;VALUE=DATE-TIME:20091015T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09230@ictp.it
DESCRIPTION:In this talk\, I will discuss unconventional superfluid states
of various bosonic systems and present benchmark calculations for the gro
und state and finite temperature phase diagrams. The method of study is b
ased on quantum Monte Carlo simulations by the Worm algorithm. The two qu
alitatively different systems to be discussed are: i) superfluidity of low
er dimensional objects\, i.e. dislocations and defects\, embedded in solid
structures both in optical lattices and in realistic systems such as 4-He
. ii) the two-component Bose-Hubbard model. Bosonic optical lattice syste
ms are also interesting for studies of quantum magnetism where under certa
in conditions they can be mapped onto various spin Hamiltonians. On the o
ther hand\, superfluid dislocations in 4-He are an important subject for t
heir relevance to supersolid behavior observed in solid 4-He.\n\n//indico.
ictp.it/event/a09230/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09230/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Nernst eff
ect and dimensionality in the quantum limit and beyond"\n\n
DTSTART;VALUE=DATE-TIME:20091022T100000Z
DTEND;VALUE=DATE-TIME:20091022T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09232@ictp.it
DESCRIPTION:Because of their very small carrier density\, bismuth and grap
hite allow to attain the quantum limit in a bulk metal with available magn
etic fields. The fate of a three-dimensional electron gas pushed to this
ultra-quantum regime remains an open question.\nRecent measurements of the
Nernst effect in graphite and in graphene combined to what was reported i
n bulk bismuth a few years ago\, and in two-dimensional electron systems a
decade earlier\, permits to draw a striking correlation between the field
profile of the Nernst response and dimensionality. When a Landau level i
ntersects the Fermi level\, the Nernst signal peaks in three-dimensional s
ystems and vanishes in two-dimensional systems. We argue that this quali
tative difference is a signature of a topological phase transition exclusi
ve to three-dimensional systems.\nBeyond the quantum limit\, when all carr
iers are confined to the first Landau level\, Nernst effect in bismuth det
ects field scales\, which are not expected in the one-particle picture. T
he field profile of these anomalies points to a bulk origin. According to
our recent angular-dependent Nernst measurements\, the band picture is qui
te successful in explaining the complex electronic spectrum of bismuth up
to 9 T\, but is inadequate as the quantum limit is crossed. In particular
\, in the vicinity of 40 T\, that is more than four times the quantum limi
t\, large anomalies in all transport properties point to an enigmatic reor
ganization of bulk electrons. Unexpectedly\, this electronic instability l
eads to an enhanced conductivity and a better metallicity.\n\n//indico.ic
tp.it/event/a09232/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09232/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "On electro
n magnetism of antiferromagnetic conductors"\n\n
DTSTART;VALUE=DATE-TIME:20091029T100000Z
DTEND;VALUE=DATE-TIME:20091029T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09238@ictp.it
DESCRIPTION:Essential dependence of the electron g-factor on the quasipart
icle momentum is a fundamental and\, so far\, largely overlooked property
of antiferromagnetic conductors. I will discuss its symmetry underpinning
s and some of its experimental consequences.\n\nThe predictions may be rel
evant to a number of antiferromagnetic conductors\, ranging from chromium
to electron- and hole-doped cuprates\, borocarbides\, iron pnictides\, org
anic and heavy fermion materials.\n\n//indico.ictp.it/event/a09238/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09238/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SEMINAR on Disorder and Strong Electron Correlations: "Topological
quantum criticality of Dirac fermions: From graphene to topological insul
ators"\n\n\n
DTSTART;VALUE=DATE-TIME:20091105T100000Z
DTEND;VALUE=DATE-TIME:20091105T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09240@ictp.it
DESCRIPTION:Critical phenomena and quantum phase transitions are paradigma
tic concepts in modern condensed matter physics. A central example in the
field of mesoscopic physics is the localization-delocalization (metal-insu
lator) quantum phase transition driven by disorder -- the Anderson transit
ion. Although the notion of localization has appeared half a century ago\,
this field is still full of surprising new developments. In this talk\,
I will discuss novel materials---graphene and topological insulators---whe
re the charge carriers have a character of 2D Dirac fermions. A non-trivia
l topological nature of the corresponding theories leads to remarkable phy
sical consequences. In graphene\, the charge carriers turn out to be topol
ogically protected from Anderson localization\, as long as the intervalley
scattering can be neglected. A similar phenomenon takes place for surface
modes of a 3D topological insulator. Furthermore\, we show that\, in the
latter system\, the Coulomb interaction leads to emergence of a quantum cr
itical state. Remarkably\, the interaction-induced critical state emerges
on the surface of a three-dimensional topological insulator without any ad
justable parameters. This ``self-organized quantum criticality'' is a nove
l concept in the field of interacting disordered systems. Finally\, we pre
dict a quantum spin-Hall transition between the normal and topological ins
ulator phases in 2D that occurs via a similar (or identical) quantum criti
cal point.\n\n//indico.ictp.it/event/a09240/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09240/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club Seminar on Disorder and strong electron correlations:
"Purely electronic transport in strongly disordered\, but nearly supercon
ducting insulators"\n\n
DTSTART;VALUE=DATE-TIME:20091106T100000Z
DTEND;VALUE=DATE-TIME:20091106T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09243@ictp.it
DESCRIPTION:Certain strongly disordered superconducting films\, when drive
n insulating by reducing thickness or by a small perpendicular magnetic fi
eld\, are believed to maintain a strong pairing of electrons into localize
d Cooper pairs\, the phase transition to an insulator merely signaling the
loss of phase coherence across the sample. The ensuing bosonic insulator
has a variety of very peculiar properties: empirically\, it is found to e
xhibit a simply activated resistance of purely electronic nature.\nI will
analyze the new question of the spectral properties of the disordered inte
racting system across the phase transition in the light of the phenomenon
of localization in Fock space. This analysis leads to a possible explanati
on of the above-mentioned properties in terms of localized Cooper pairs wh
ich couple only very weakly to phonons. Open and controversial issues will
be discussed.\n\nREFERENCES:\n\nM. Müller\, arXiv:0909.2260\nI.L. Aleine
r\, B.L. Altshuler\, G.V. Shlyapnikov\, arXiv:0910.4534\n\n//indico.ictp.i
t/event/a09243/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09243/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "The energy landscap
e of glassy systems or Long time dynamics in mean field glassy models"
DTSTART;VALUE=DATE-TIME:20091110T100000Z
DTEND;VALUE=DATE-TIME:20091110T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09242@ictp.it
DESCRIPTION:Mean field glassy system have been the subject of much studies
over the last decades. They arise as mean field models for the glass tran
sition\, but also as models for complex systems and optimization problems.
Their thermodynamics properties can be solve using the replica\, or the c
avity method.\n\nIn this talk\, I will introduce a generalization of the c
avity method that allows to follow Gibbs states in mean field systems when
an external parameter\, e.g. the temperature\, is tuned. The method thus
yields a "static" way to study long time "dynamics" in mean field models o
f glass formers\, spin glasses\, or random constraint satisfaction problem
s. In optimization problems the method gives limits for the performance of
the simulated annealing algorithm. It also gives new results on the stabi
lity and the marginality of the non-equilibrium states\, on the spinodal p
oint upon heating\, and allow to demonstrate the presence of temperature c
haos.\n\nReference : Krzakala\, Zdeborova \; arXiv:0909.3820v1.\n\n//indic
o.ictp.it/event/a09242/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09242/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Statistical Physics: "From vicious walkers to
random matrix theory: A path-integral approach"\n\n
DTSTART;VALUE=DATE-TIME:20091111T150000Z
DTEND;VALUE=DATE-TIME:20091111T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09246@ictp.it
DESCRIPTION:Vicious\, i.e. non-intersecting\, random walkers have been stu
died in various physical situations\, ranging from wetting and melting to
stochastic growth processes. In this talk\, I will present a method based
on path integrals associated to free Fermions models to study such statis
tical models. In particular I will show how this allows for a physical de
rivation of the connection between certain constrained vicious walkers and
random matrix theory. Besides I will use this method to calculate exactl
y the distribution of the maximal height of p vicious walkers with and wit
hout a wall.\n\n//indico.ictp.it/event/a09246/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09246/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Anderson lo
calization of matter-waves in laser speckles"\n\n
DTSTART;VALUE=DATE-TIME:20091112T100000Z
DTEND;VALUE=DATE-TIME:20091112T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09253@ictp.it
DESCRIPTION:Predicted in 1958 by P. W. Anderson for electronic waves and l
atter recognized as an ubiquitous phenomenon in wave physics\, the Anderso
n localization effect has prompted an intense experimental and theoretical
activity. Since the 90’s\, such exponential localization effects have
been reported in different types of waves (light waves\, microwaves\, sou
nd waves…) and were directly observed with matter-waves very recently [1
\,2].\n\nI will present in this seminar the scheme realized in Palaiseau w
here the propagation of a Bose Einstein condensate along a one-dimensional
waveguide is stopped in presence of a weak disorder. A stationary state
is reached and the emblematic signature of AL (e.g. the exponential decay
in the tails) is directly observed by imaging. The disorder potential is
created by laser speckle\, whose characteristics are well controlled. Suc
h control enables a good agreement with theoretical predictions [3]. This
experiment is thus very promising in view of future extensions of the sch
eme to higher dimensions (2D or 3D) or in the presence of interactions.\n\
n [1] J. Billy et al. Nature 453 p. 891 (2008)\n [2] G. Roati et al.
Nature 453 p. 895 (2008)\n [3] L. Sanchez-Palencia et al. Phys. Rev. L
ett 98\, 210401 (2007)\n\n//indico.ictp.it/event/a09253/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09253/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Lieb-Liniger Bose g
as as the non-relativistic limit of the sinh-Gordon model"
DTSTART;VALUE=DATE-TIME:20091117T100000Z
DTEND;VALUE=DATE-TIME:20091117T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09255@ictp.it
DESCRIPTION:Due to recent experimental achievements with trapped ultracold
atoms\, the properties of the 1D non-relativistic Bose gas are of great i
nterest. In many experimental setups the behaviour of the particles is ver
y well described by the Lieb-Liniger model which in many aspects can be re
garded as a theoretical benchmark in the research of integrable models. In
spite of its integrability\, calculating correlation functions in the mod
el is notoriously difficult. In the talk I will propose a novel approach t
o compute expectation values and other physical quantities in the Lieb-Lin
iger model. The method is based on the fact that in the repulsive case the
S-matrix\, the Lagrangian and the operators can be obtained from a certai
n non-relativistic limit of the sinh-Gordon model. This observation allows
us to compute expectation values both at zero and finite temperature. Amo
ng other results\, I present the computation of the three-body correlation
function at finite temperature\, which is closely related to the recombin
ation rate of the gas.\n\n//indico.ictp.it/event/a09255/
LOCATION:Lecture Room D - SISSA Main Building
URL://indico.ictp.it/event/a09255/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter seminar: "Excitations in bilayer
graphene in high magnetic field"
DTSTART;VALUE=DATE-TIME:20091118T150000Z
DTEND;VALUE=DATE-TIME:20091118T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09257@ictp.it
DESCRIPTION:The charge-density excitations in bilayer graphene at the fill
ing-factor \n\n//indico.ictp.it/event/a09257/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09257/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Magnetic mo
nopoles in spin ice"\n
DTSTART;VALUE=DATE-TIME:20091119T100000Z
DTEND;VALUE=DATE-TIME:20091119T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09256@ictp.it
DESCRIPTION:Electrically charged particles\, such as the electron\, are ub
iquitous. By contrast\, no elementary particles with a net magnetic charg
e have ever been observed\, despite intensive and prolonged searches.\n\nA
n alternative strategy is to realise them not as elementary but rather as
emergent particles\, i.e.\, as manifestations of the correlations present
in a strongly interacting many-body system. Indeed\, it turns out that m
agnetic monopoles do emerge in a class of exotic magnets known collectivel
y as spin ice: the dipole moment of the underlying electronic degrees of f
reedom fractionalises into monopoles! These monopoles can in principle be
detected in an experiment modelled after the celebrated Stanford search f
or magnetic monopoles of cosmic origin. The many-body state of spin ice\,
in turn\, represents a new type of phase outside the standard classific
ation of magnetic order and disorder.\n\nReference: C. Castelnovo\, R. Moe
ssner and S. L. Sondhi\, Nature 451\, 42 (2008).\n\n//indico.ictp.it/event
/a09256/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09256/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Bogoliubov Theory o
f acoustic Hawking radiation in Bose-Einstein Condensates"
DTSTART;VALUE=DATE-TIME:20091124T100000Z
DTEND;VALUE=DATE-TIME:20091124T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09261@ictp.it
DESCRIPTION:We apply the microscopic Bogoliubov theory of dilute Bose-Eins
tein condensates to analyze quantum and thermal fluctuations in a flowing
atomic condensate in the presence of a sonic horizon. For the simplest cas
e of a step-like horizon\, closed-form analytical expressions are found fo
r the spectral distribution of the analog Hawking radiation and for the de
nsity correlation function. The peculiar long-distance density correlation
s that appear as a consequence of the Hawking emission features turns out
to be reinforced by a finite initial temperature of the condensate. The an
alytical results are in good quantitative agreement with first principle n
umerical calculations.\n\n//indico.ictp.it/event/a09261/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09261/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR - SPECIAL SEMINAR: "U
nbalanced strongly interacting Fermi gas"
DTSTART;VALUE=DATE-TIME:20091126T100000Z
DTEND;VALUE=DATE-TIME:20091126T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09262@ictp.it
DESCRIPTION:We study the zero temperature properties of a trapped polarize
d Fermi gas at unitarity by assuming phase separation between an unpolariz
ed superfluid and a polarized normal phase. The effects of the interaction
are accounted for using the formalism of quasiparticles to build up the e
quation of state of the normal phase. Our predictions for the Chandrasekha
r-Clogston limit of critical polarization and for the density profiles\, i
ncluding the density jump at the interface\, are confirmed with excellent
accuracy by the recent experimental results. The role of interaction on th
e radial width of the minority component\, on the gap of spectral function
s\, and on the spin oscillations in the normal phase is also discussed. Ou
r analysis points out the Fermi liquid nature of these strongly interactin
g spin-polarized configurations.\n\n//indico.ictp.it/event/a09262/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09262/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Interactive Learnin
g"
DTSTART;VALUE=DATE-TIME:20091201T100000Z
DTEND;VALUE=DATE-TIME:20091201T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09265@ictp.it
DESCRIPTION:I present a quantitative approach to interactive learning and
adaptive behavior\, which integrates model- and decision-making into one t
heoretical framework. This approach follows simple principles by requiring
that the observers behavior and the observers internal representation of
the world should result in maximal predictive power at minimal complexity.
Classes of optimal action policies and of optimal models can be derived f
rom an objective function that reflects this trade-off between prediction
and complexity. The resulting optimal models then summarize\, at different
levels of abstraction\, the process causal organization in the presence o
f the feedback due to the learners actions. A fundamental consequence of t
he proposed principle is that the optimal action policies have the emergin
g property that they balance exploration and control. Interestingly\, the
explorative component is present also in the absence of policy randomness\
, i.e. in the optimal deterministic behavior. Exploration is therefore not
the same as policy randomization. This is a direct result of requiring ma
ximal predictive power in the presence of feedback. It stands in contrast
to\, for example\, Boltzmann exploration\, which is frequently used in Rei
nforcement Learning (RL). Time permitting\, I will discuss what happens wh
en one includes explicit goals and rewards into the theory\, as is popular
in RL.\n\n//indico.ictp.it/event/a09265/
LOCATION:Lecture Room D - SISSA Main Building
URL://indico.ictp.it/event/a09265/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "A 'quantum
mechanical' view on the dynamical glass transition"
DTSTART;VALUE=DATE-TIME:20091203T100000Z
DTEND;VALUE=DATE-TIME:20091203T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09267@ictp.it
DESCRIPTION:Using the mapping from the Fokker-Planck description of classi
cal stochastic dynamics into a quantum Hamiltonian\, we argue that a dynam
ical glass transition can be given a precise definition in terms of a stat
ic (equilibrium) quantum phase transition. This transition is characterize
d by a massive collapse of the excited states\, leading to a divergent sta
tic quantum susceptibility throughout the glassy phase\, which directly re
lates to a non-vanishing Edwards-Anderson order parameter. The quantum me
chanical language allows to search for off-diagonal order parameters to de
tect the classical ‘dynamic order’ using transverse bases – an appro
ach that corresponds to non-static observables in the original classical l
anguage. Even in the absence of a local order parameter\, the transition
can be detected via quantum fidelity measures on the ground state wavefunc
tion\, which we show to translate directly into a singularity in the heat
capacity of the classical system.\n\n//indico.ictp.it/event/a09267/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09267/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club seminar on Disorder and strong electron correlations:
"A geometrical derivation of entanglement entropy using the AdS/CFT corre
spondence"
DTSTART;VALUE=DATE-TIME:20091204T100000Z
DTEND;VALUE=DATE-TIME:20091204T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09268@ictp.it
DESCRIPTION:The entanglement entropy of a quantum critical system in d+1-d
imensions described by a Conformal Field Theory is calculated as the "area
" of a d-dimensional minimal surface in a d+2-dimensional Anti-deSitter sp
ace. This formulation is analogous to the Bekenstein-Hawking formula for t
he black hole entropy.\n\nReference: S. Ryu and T. Takayanagi\, PRL 96\, 1
81602 (2006)\n\n//indico.ictp.it/event/a09268/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09268/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Graphene el
ectronics"\n
DTSTART;VALUE=DATE-TIME:20091211T100000Z
DTEND;VALUE=DATE-TIME:20091211T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09270@ictp.it
DESCRIPTION:Graphene is a new material consisting of a one-atom-thick laye
r of graphite. It has been discovered only a few years ago and since its
discovery it has shown to possess many unique and fascinating properties.
These properties are a consequence of the fact that electrons in graphene
effectively behave as massless relativistic electrons\, whose dynamics is
described by the two-dimensional Dirac equation. In this talk I will firs
t introduce the field\, by explaining in some detail how the electronic pr
operties of graphene originate\, how they manifest themselves in the exper
iments\, and how the experiments are actually done. I will then move to d
iscuss more specific topics that we have investigated during the past few
years. These include phase coherent transport of electrons (Aharonov-Bohm
effect\, weak-localization\, Josephson supercurrent)\, finite conductivity
at the charge neutrality point\, and gate-tunable band structure. Taken
together\, these examples make clear that graphene (single-layers as well
as materials consisting of a small number of layers) indeed is a unique ma
terial system\, in which the discovery of new physical phenomena can be ex
pected\, and which could be of use in future electronic applications.\n\n/
/indico.ictp.it/event/a09270/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a09270/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Algorithmic complex
ity and quantum dynamics"
DTSTART;VALUE=DATE-TIME:20091215T100000Z
DTEND;VALUE=DATE-TIME:20091215T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a09271@ictp.it
DESCRIPTION:Algorithmic complexity is a powerful tool that\, in the realm
of classical dynamical systems\, gives solid ground to the intuitive notio
ns of chaoticness and randomness. Possible generalizations to quantum dyna
mical systems will be presented and discussed within the context of quantu
m information theory.\n\n//indico.ictp.it/event/a09271/
LOCATION:Lecture Room D - SISSA Main Building
URL://indico.ictp.it/event/a09271/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Casimir effects: Ph
ysical manifestations of the quantum vacuum"
DTSTART;VALUE=DATE-TIME:20100119T100000Z
DTEND;VALUE=DATE-TIME:20100119T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a104@ictp.it
DESCRIPTION:The forces and torques among macroscopic objects caused by flu
ctuating quantum fields are known as Casimir effects after the Dutch theor
etician who discovered them in the late 1940's. Recent high precision exp
eriments and emerging micro-electromechanical applications have generated
great interest in the nature\, properties\, and manipulation of Casimir ef
fects. I will discuss the origins\, interpretation\, and computation of C
asimir effects. In particular I will outline the development of a powerfu
l method to compute Casimir forces and torques based on classical scatteri
ng theory. I will survey some of the results obtained with these methods.
\n\n//indico.ictp.it/event/a104/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a104/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter seminar: "Effects of isotopic ma
ss and temperature on the optical properties of semiconductors"
DTSTART;VALUE=DATE-TIME:20100120T150000Z
DTEND;VALUE=DATE-TIME:20100120T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a102@ictp.it
DESCRIPTION:The state of the art calculations of the dielectric function o
f semiconductors will be reviewed and compared with extant experimental da
ta. Most of the comparisons available in the literature suffer from the fa
ct that the calculations are performed with the atoms at fixed lattice pos
itions\, whereas the experimental data are often taken at room temperature
. Even when the latter have been obtained at low temperatures\, close to 0
K\, they are affected by the zero-point vibrations\, a quantum mechanical
effect which can be varied by changing the isotopic masses of the constitu
ent atoms. In recent years samples with different isotopic compositions ha
ve become available. Measurements on such samples make possible to determi
ne the renormalization of the dielectric function and other physical prope
rties effected by the lattice vibrations (zero point and temperature effec
ts). This renormalization is particularly large in crystals with light ato
ms (diamond\, ZnO\, GaN)\, a fact that signals a rather strong electron ph
onon interaction. This strong interaction is responsible for the supercond
uctivity recently observed in boron-doped diamond (also Si and SiC).\n\n//
indico.ictp.it/event/a102/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a102/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Scattering theory approa
ch to electrodynamic Casimir interactions"\n
DTSTART;VALUE=DATE-TIME:20100121T100000Z
DTEND;VALUE=DATE-TIME:20100121T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a108@ictp.it
DESCRIPTION:We have derived methods for calculating the Casimir force to a
rbitrary accuracy\, for any number of objects\, arbitrary shapes\, suscept
ibility functions\, and separations. The technique is applicable to objec
ts immersed in media other than vacuum\, nonzero temperatures\, and spatia
l arrangements in which one object is enclosed in another. The method com
bines each object's classical electromagnetic scattering amplitude with un
iversal translation matrices\, which convert between the bases used to cal
culate scattering for each object\, but are otherwise independent of the d
etails of the individual objects. We have explored various novel geometri
es using these techniques\, including objects interacting with cavities an
d objects with sharp edges.\nThe method is further used to examine whether
fluctuation-induced forces can lead to stable levitation. Neglecting perm
eabilities\, we find that any equilibrium position of items subject to suc
h forces is also unstable if the permittivities of all objects are higher
or lower than that of the enveloping medium\; the former being the generic
case for ordinary materials in vacuum. Thus\, the Casimir force cannot pr
oduce stable equilibria in vacuum for ordinary materials.\n\n//indico.ictp
.it/event/a108/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a108/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "The amazing unitary
Fermi gas"
DTSTART;VALUE=DATE-TIME:20100126T100000Z
DTEND;VALUE=DATE-TIME:20100126T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a103@ictp.it
DESCRIPTION:We discuss the amazing properties of the unitary Fermi gas\, w
hich is the dilute and ultracold gas of fermions with infinite scattering
length. Then\, we illustrate the zero-temperature density functional of th
e unitary Fermi gas we have recently introduced on the basis of Monte Carl
o calculations. This functional includes a gradient term which is essentia
l to describe accurately the surface effects of the system\, in particular
with a small number of atoms. We analyze in detail the role of this gradi
ent term for the determination of density profiles and collective modes. F
inally\, we investigate the low-temperature thermodynamics of the unitary
Fermi gas by using the zero-temperature spectra of both bosonic collective
modes and fermonic single-particle excitations. We determine the superflu
id fraction\, the critical temperature\, the first sound and the second so
und\, comparing our analytical results with other theoretical predictions
and experimental data.\n\n//indico.ictp.it/event/a103/
LOCATION:SISSA Main Bldg.-Lecture Room'D'
URL://indico.ictp.it/event/a103/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "On the collective b
ehaviour of large numbers of flying birds: The case of Sturnus vulgaris"
\n
DTSTART;VALUE=DATE-TIME:20100128T133000Z
DTEND;VALUE=DATE-TIME:20100128T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1014@ictp.it
DESCRIPTION://indico.ictp.it/event/a1014/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a1014/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Spin tensor
phases in frustrated magnets"
DTSTART;VALUE=DATE-TIME:20100128T100000Z
DTEND;VALUE=DATE-TIME:20100128T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1015@ictp.it
DESCRIPTION:Strong geometrical frustration precludes conventional magnetic
ordering. A common outcome is a completely disordered spin-liquid state
at zero and at low temperatures. Another interesting possibility is a pa
rtial breaking of spin rotational symmetry described by spin-tensor order
parameters. We shall discuss two examples of such unusual symmetry breaki
ng. The first model example is a classical Heisenberg antiferromagnet on
a kagome lattice [1]. At low temperatures the order by disorder mechanism
selects a submanifold of planar spin states which are described by non-ze
ro octupole moments. An interesting consequence of such a third-rank tens
or order parameter is presence of various types of fractional vortices. T
he second example is a system of weakly coupled spin-1/2 frustrated ferrom
agnetic chains [2]. The high-field transition from the saturated phase oc
curs via condensation of bound magnon pairs. Such a condensate of is desc
ribed by spin-nematic or second-rank tensor. We develop analytical theory
for the bose condensation into nematic state and argue that corresponding
transition is realized in LiCuVO4.\n\n[1] M. E. Zhitomirsky\, Phys. Rev.
B {78}\, 094423 (2008).\n [2] H. Tsunetsugu and M. E. Zhitomirsky\, in pro
gress (2010).\n\n//indico.ictp.it/event/a1015/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a1015/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Quantum quenches in
interacting theories"
DTSTART;VALUE=DATE-TIME:20100202T100000Z
DTEND;VALUE=DATE-TIME:20100202T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1023@ictp.it
DESCRIPTION:The time evolution following a quantum quench\, i.e. an instan
taneous change in the parameters of an isolated quantum system\, has been
shown to lead\, in a wide range of models and under quite general conditio
ns\, to stationary behaviour with some thermal characteristics. After a r
eview of free field theory results that introduces necessary new concepts
and tools\, we investigate a quantum quench in the phi^4 model in a self-c
onsistent approximation. A direct application of perturbation theory is n
ot suitable in this case and resummation of Feynman diagrams is needed. W
e propose an ansatz for the long time behaviour of the system\, which we v
erify by a self-consistency calculation and numerical integration of the e
quations of motion.\n\n//indico.ictp.it/event/a1023/
LOCATION:SISSA - Lecture Room 'D'
URL://indico.ictp.it/event/a1023/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/Democritos Informal Seminar on Chemical Physics:\n"Elec
tronic structure and thermal properties of semiconductor early transition
metal nitrides"
DTSTART;VALUE=DATE-TIME:20100202T130000Z
DTEND;VALUE=DATE-TIME:20100202T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1024@ictp.it
DESCRIPTION://indico.ictp.it/event/a1024/
LOCATION:ICTP Leonardo da Vinci Building Oppenheimer Meeting Room
URL://indico.ictp.it/event/a1024/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Spin glass
transition in geometrically frustrated antiferromagnets with weak disorder
"
DTSTART;VALUE=DATE-TIME:20100204T100000Z
DTEND;VALUE=DATE-TIME:20100204T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1025@ictp.it
DESCRIPTION:We study the effect in geometrically frustrated antiferromagne
ts of weak\, random variations in the strength of exchange interactions.
Without disorder the simplest classical models for these systems have macr
oscopically degenerate ground states\, and this degeneracy may prevent ord
ering at any temperature. Weak exchange randomness favours a small subset
of these ground states and induces a spin-glass transition at an ordering
temperature determined by the amplitude of modulations in interaction stre
ngth. We use the replica approach to formulate a theory for this transitio
n\, showing that it falls into the same universality class as conventional
spin-glass transitions. In addition\, we show that a model with a low con
centration of defect bonds can be mapped onto a system of randomly located
pseudospins that have dipolar effective interactions. We also present de
tailed results from Monte Carlo simulations of the classical Heisenberg an
tiferromagnet on the pyrochlore lattice with weak randomness in nearest ne
ighbour exchange.\n\n//indico.ictp.it/event/a1025/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a1025/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Game theory and net
works"
DTSTART;VALUE=DATE-TIME:20100209T100000Z
DTEND;VALUE=DATE-TIME:20100209T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1031@ictp.it
DESCRIPTION:The framework of non-cooperative game theory has been recently
extended to study strategic behavior in complex socio-economic networks.
However\, the existence of a large number of (very different) Nash equili
bria makes standard game theoretic analysis cumbersome and quantitatively
less effective. On the other hand\, it opens to the application of advance
d theoretical and algorithmic techniques from the statistical mechanics of
disordered systems.\nI will discuss our recent results on the problem of
free-riding in public goods games and on the emergence of collaborative eq
uilibria.\n\n//indico.ictp.it/event/a1031/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a1031/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Strongly co
rrelated states in low dimensional Bose gases"\n\n
DTSTART;VALUE=DATE-TIME:20100211T100000Z
DTEND;VALUE=DATE-TIME:20100211T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1034@ictp.it
DESCRIPTION:Ultracold atoms can be trapped in strongly confined low dimens
ional trap geometries like (1D) cigars and (2D) pancakes: this allows for
to experimentally simulate Hamiltonians having strongly correlated ground
states. The 1D Bose gas is well described by the so called Lieb-Liniger H
amiltonian: in the talk I will discuss a recently proposed method to compu
te expectation values and other physical quantities. The method is based
on the observation that the S-matrix and the Lagrangian of the Lieb-Linige
r model can be obtained as a non-relativistic limit of an integrable relat
ivistic field theory\, the sinh-Gordon model. In the final part of the ta
lk\, I will briefly discuss the effect of an experimentally realizable art
ificial non-abelian magnetic field acting on a 2D ultracold atomic gas\, s
howing that it is possible to tune the Hamiltonian parameters in order to
have non-abelian excitations.\n\n//indico.ictp.it/event/a1034/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a1034/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Exact entanglement
entropy of the XYZ model and its sine-Gordon limit"\n
DTSTART;VALUE=DATE-TIME:20100216T100000Z
DTEND;VALUE=DATE-TIME:20100216T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1037@ictp.it
DESCRIPTION:We obtain the exact expression for the Von Neumann entropy for
an infinite bipartition of the XYZ model\, by connecting its reduced dens
ity matrix to the corner transfer matrix of the eight vertex model. Then
we consider the anisotropic scaling limit of the XYZ chain that yields the
1+1 dimensional sine-Gordon model. We present the formula for the entangl
ement entropy of the latter\, which has the structure of a dominant logari
thmic term plus a constant\, in agreement with what is generally expected
for a massive quantum field theory.\n\n//indico.ictp.it/event/a1037/
LOCATION:SISSA Main Bldg.- Room 'D'
URL://indico.ictp.it/event/a1037/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter seminar: "What makes superconduc
tivity happen at high temperature?"\n
DTSTART;VALUE=DATE-TIME:20100217T150000Z
DTEND;VALUE=DATE-TIME:20100217T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1033@ictp.it
DESCRIPTION:Superconductivity and magnetism are often considered as antago
nistic phenomena. Indeed the phenomenon of superconductivity is usually o
bserved in materials showing no instabilities toward magnetic order of any
kind. However\, in recent decades several new classes of superconductors
have been discovered where superconductivity occurs on the brink of magne
tic order\, and in a limited number of examples coexistence of superconduc
tivity and ferromagnetism has even been claimed. In many of these new mat
erials the Cooper-pairs were observed and/or predicted to have finite angu
lar momentum\, and sometimes even finite spin. The field of superconducti
vity has\, so to speak\, become very 'rich' and ever so more fascinating.
In this Colloquium I will\, based on the state of affairs in unconvention
al superconductivity\, argue in favour of the scenario where high temperat
ure superconductivity arises from pairing mediated through the virtual exc
hange of spin fluctuations. This is born out by a vast body of experiment
al data obtained worldwide using photo-electron spectroscopy\, tunnelling
and optics. These experiments have enabled the community to establish the
temperature and energy dependence of the dissipation and the mass renorma
lization of the charge carriers in various materials including the high Tc
superconductors. Based on the energy range observed for the inelastic sc
attering\, it is now possible to eliminate phonon mediated pairing as 'the
' mechanism of superconductivity in the cuprates\, and provide quantitativ
e arguments in favour of the thesis that superconductivity in these materi
als is driven by proximity to magnetic (or stripe) instability.\n\n//indic
o.ictp.it/event/a1033/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a1033/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SEMINAR on Disorder and strong electron correlations: "Non-abelia
n anyons and topological quantum computation"
DTSTART;VALUE=DATE-TIME:20100218T100000Z
DTEND;VALUE=DATE-TIME:20100218T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1040@ictp.it
DESCRIPTION:The main topic of this seminar is the theory of non-Abelian an
yons. The exotic statistical properties of such excitations make it possib
le to set up quantum computational schemes based on robust topological pro
perties as those of knots and braids. Although still in its infancy\, topo
logical quantum computation promises to be the catalysis for a very produc
tive merging of ideas coming from several fields of physics\, mathematics
and computer science.\n\n//indico.ictp.it/event/a1040/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a1040/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Explosive Percolati
on"
DTSTART;VALUE=DATE-TIME:20100223T100000Z
DTEND;VALUE=DATE-TIME:20100223T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1042@ictp.it
DESCRIPTION:A biased link occupation rule discourages the growth of large
clusters much ahead of others and encourages faster growth of clusters whi
ch lag behind. The resulting percolation transition\, proposed recently\,
is discontinuous\, and referred to as 'Explosive percolation'. We will dis
cuss the results on a variety of graphs. We also introduce a new model wit
h a single parameter alpha\, and show that the transition is discontinuous
for alpha \n\n//indico.ictp.it/event/a1042/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a1042/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Criticality
\, shocks and avalanches in spin glasses"\n
DTSTART;VALUE=DATE-TIME:20100225T100000Z
DTEND;VALUE=DATE-TIME:20100225T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1045@ictp.it
DESCRIPTION:The low temperature phase of spin glasses exhibits algebraical
ly decaying spin-spin correlations at all T ~ exp(-omega t*) and compute the characteristic time
\, t*\, of this dependence.\n\nIn a typical disordered system a significan
t number of spins have a strongly coupled neighbor. We show that this\, t
ogether with the exponential decrease of the spin correlator at high frequ
encies translates into a low-frequency 1/f noise in all physical quantitie
s sensitive to the spin state of the strongly coupled pairs. We discuss t
he application of these results to the problem of susceptibility and flux
noise in superconducting circuits.\n\nWork in collaboration with Lev Ioffe
and Alexei Kitaev.\n\n//indico.ictp.it/event/a10312/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a10312/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Unusual Corrections
to Scaling in Entanglement Entropy"
DTSTART;VALUE=DATE-TIME:20101214T100000Z
DTEND;VALUE=DATE-TIME:20101214T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a10329@ictp.it
DESCRIPTION:The study of the entanglement properties of the ground-state o
f an extended quantum system has prompted an intense research activity at
the crossroad of different disciplines such as statistical mechanics\, qua
ntum information\, and quantum filed theory. Quantifying the entanglement
allowed an elegant and finer characterization of many extended quantum sy
stems.\nIn this talk\, after reviewing the results for one-dimensional sys
tems at a quantum critical point that are described by a conformal invaria
nt field theory\, I will consider the corrections to the asymptotic behavi
or. I will show that leading corrections are unusual\, in the sense that
they depend (in a calculable way) on the entanglement measure and they ari
se from relevant operators induced by the conical space-time singularities
necessary to describe the reduced density matrix.\n\n//indico.ictp.it/eve
nt/a10329/
LOCATION:SISSA\, Santorio Building\, Room 129 (1st Floor
URL://indico.ictp.it/event/a10329/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Solids\, su
persolids\, and pairing with dipolar bosons in optical lattices"\n
DTSTART;VALUE=DATE-TIME:20101216T103000Z
DTEND;VALUE=DATE-TIME:20101216T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a10330@ictp.it
DESCRIPTION:We discuss dipolar bosons trapped in single layer and multilay
er optical lattices and study quantum phases stabilized by the long range
dipolar interaction. Such systems can be realized experimentally by ultra
cold samples of polar molecules. We have observed solid\, supersolid and
pairing phases. The latter can be stabilized in the presence of a mixture
of atoms and polar molecules\, and in multilayered systems. Our results
are based on quantum Monte Carlo simulations and are exact in a statistica
l sense.\n\n//indico.ictp.it/event/a10330/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a10330/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar: "Manipulation of charge\, spin and conformation
in atoms and molecules"\n
DTSTART;VALUE=DATE-TIME:20101220T100000Z
DTEND;VALUE=DATE-TIME:20101220T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a10333@ictp.it
DESCRIPTION:Scanning tunneling microscope (STM) manipulation of single ato
ms and molecules on surfaces allow construction of novel quantum structure
s on an atom-by-atom basis and demonstration of single molecule devices on
a one molecule at-a-time basis. STM is not only an instrument used to ‘
see’ individual atoms by means of imaging\, but also a tool used to ‘t
ouch’ and ‘take’ atoms and molecules or to ‘hear’ their vibratio
n by manipulations. Therefore\, STM can be considered as the ‘eyes’\,
‘hands’ and ‘ears’ of the scientists connecting our macroscopic wo
rld to the atomic and nanoscopic world. \nIn our research projects\, we co
mbine a variety of STM manipulation schemes with tunneling spectroscopy te
chniques to investigate properties of atoms and molecules on surfaces. Thi
s talk will include our recent results and achievements\; in spintronic re
search area\, we will demonstrate that not only manipulation of magnetic a
toms can be done but also imaging the direction of spin is possible by usi
ng a magnetic STM tip [1]. In superconductivity area\, we will present the
smallest molecular superconductor ever studied to date. Here\, the findin
g of superconductivity in just four pairs of (BETS)2-GaCl4 molecules not o
nly provides the possibility of investigating this phenomenon locally\, bu
t also opens potential applications in nanoelectronics [2]. In molecular s
pintronics area\, orbital Kondo effect of TBrPP-Co molecules generated by
an interfacial charge transfer process will be discussed [3]. Finally\, in
molecular nanomachines area\, complex rotation mechanisms of Ru based dou
bled decker molecular rotors operated by injecting tunneling electrons fro
m an STM tip will be presented. These experiments are innovative\, and are
tailored to address several critical issues covering both for fundamental
understanding\, and for demonstration of novel atom/molecule based nanode
vices. \n\n[1] D. Serrate\, P. Ferriani\, Y. Yoshida\, S.-W. Hla\, M. Menz
el\, K. von Bergmann\, S. Heinze\, A. Kubetzka\, and R.\nWiesendanger. Ima
ging and Manipulating the Spin Direction of Individual Atoms. Nature Nanot
echnology 5 (2010) 350-354.\n[2]. K. Clark\, A. Hassanien\, S. Khan\, K.-F
. Braun\, H. Tanaka\, and S.-W. Hla. Superconductivity in Just Four\nPairs
of (BETS)2 GaCl4 Molecules. Nature Nanotechnology 5 (2010) 261-265.\n[3].
U.G.E. Perera\, H. Kulik\, V. Iancu\, LGGV\, Dias da Silva\, S.E. Ulloa\,
N. Marzari\, and S.-W. Hla. Spatially Extended Kondo States in Magnetic M
olecules Induced by an Interfacial Charge Transfer. Phys. Rev. Lett. 105 (
2010) 106601.\n\n//indico.ictp.it/event/a10333/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a10333/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "The weakly coupled
Pfaffian as a Type I quantum Hall liquid"\n
DTSTART;VALUE=DATE-TIME:20101221T103000Z
DTEND;VALUE=DATE-TIME:20101221T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a10334@ictp.it
DESCRIPTION:The Pfaffian phase of electrons in the proximity of a half-fil
led Landau level is understood to be a p+ip superconductor of composite fe
rmions. We consider the properties of this paired quantum Hall phase when
the pairing scale is small\, i.e. in the weak-coupling\, BCS\, limit\, wh
ere the coherence length is much larger than the charge screening length.
We find that\, as in a Type I superconductor\, the vortices attract so th
at\, upon varying the magnetic field from its magic value at \\nu=5/2\, th
e system exhibits Coulomb frustrated phase separation. We propose that th
e weakly and strongly coupled Pfaffian states exemplify a general dichotom
y between Type I and Type II quantum Hall fluids.\n\n//indico.ictp.it/even
t/a10334/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a10334/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Spectra of products
of Gaussian random matrices"\n
DTSTART;VALUE=DATE-TIME:20110118T103000Z
DTEND;VALUE=DATE-TIME:20110118T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a115@ictp.it
DESCRIPTION:Some spectral properties of products of random matrices are di
scussed. In particular\, exact analytic expression related to the eigenva
lue and singular value distributions for the product of an arbitrary numbe
r of independent rectangular Gaussian random matrices are derived in the l
imit of large matrix dimensions. The eigenvalue density is obtained by me
ans of a planar diagrammatic technique\, which will be outlined in great d
etail throughout the talk\, while the singular value density is derived in
the framework of Free Probability\, the extension of ordinary probability
theory to non-commuting objects. Both distributions are shown to display
a power-law behavior at zero. A heuristic form for finite size correction
s to these expressions which very well approximates the distributions for
matrices of finite dimensions is proposed. All results are compared to em
pirical spectra\, finding an excellent overall agreement between theory an
d data. Also\, some possible applications to information theory and to pr
oblems of multivariate statistics are discussed.\n\n//indico.ictp.it/event
/a115/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a115/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Quantum spin Hamilt
onian for the SU(2) Wess-Zumino-Witten model" \n
DTSTART;VALUE=DATE-TIME:20110125T100000Z
DTEND;VALUE=DATE-TIME:20110125T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1110@ictp.it
DESCRIPTION:We show that the chiral correlators of the SU(2) level k WZW
model can be used as ground states of quantum spin chains. Employing the
null vectors of this Rational CFT\, we construct the corresponding Hamilt
onians. At level k=1 we recover the Haldane-Shastry spin chain which is
generalized to study dimerized and random chains. At level k=2 we constr
uct a spin 1 chain whose ground state is a pfaffian\, and a spin 1/2 chain
whose ground state is degenerate\, according to the fusion rules of the
WZW. These models are further generalized to two dimensions. We shall al
so briefly discuss the relation with the Fractional Quantum Hall wave func
tions allowing for topological quantum computation.\n\n//indico.ictp.it/e
vent/a1110/
LOCATION:SISSA\, Santorio Bldg.\, Room 129 1st floor
URL://indico.ictp.it/event/a1110/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "A tunable Bose-Eins
tein condensate in disordered potentials"\n
DTSTART;VALUE=DATE-TIME:20110201T103000Z
DTEND;VALUE=DATE-TIME:20110201T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1113@ictp.it
DESCRIPTION:We present our studies on a Bose-Einstein condensate (BEC) tra
pped in disordered potentials. The interactions between the atoms can be
controlled at will thanks to a broad magnetic Feshbach resonance \n[1]. T
he disorder is introduced into the system by means of a quasi-periodic lat
tice generated by superimposing two laser standing waves with incommensura
te wavelengths. We study two different regimes. First\, the interactions
between the particles are tuned to zero. This "ideal" gas in the bichro
matic lattice reproduces the Aubry-André hamiltonian \n[2]\, which shows
a transition between extended and exponentially localized single-particle
wavefunction\, similar to the Anderson model \n[3]. We have directly obser
ved the onset of localization by probing the momentum distribution and the
absence of diffusion of the non-interacting condensate \n[4]. In a second
experiment\, we reintroduce some repulsive interactions into the sample \
n[5]. In particular\, we investigate the interplay between disorder and in
teractions. We observe the transition from incoherent Anderson localized
states to fully coherent extended states. For large interactions the effe
ct of the disorder is highly reduced and the system enters the BEC regime.
The characterization of this superfluid to insulator transition (SIT) is
particularly important. Infact\, despite it is present in many different
physical systems such as\, for example\, helium in porous media \n[6] and
high TC superconductors \n[7]\, its complete understanding is still missin
g. We also study the diffusion of the coherent matter wave through the dis
ordered lattice \n[8]. In case of the non interacting system\, diffusion i
s absent\, since the condensate wavefunction is fully localized. When rep
ulsive interactions are added\, we instead observe a slow expansion with s
ubdiffusive behavior. Our investigations allow to get an insight on the in
terdisciplinary field of diffusion in disordered potentials in presence of
non-linearity.\n\nReferences\n[1] G. Roati et al.\, Phys. Rev. Lett. 99\,
010403 (2007)\n[2] S. Aubry and G. André\, Ann. Israel Phys. Soc. 3\, 13
3 (1980).\n[3] P. W. Anderson\, Phys. Rev. 109\, 1492 (1958).\n[4] G. Roat
i et al.\, Nature 453\, 895 (2008)\n[5] B. Deissler et al.\, Nature Physic
s 6\, 354-358 (2010)\n[6] J. D. Reppy\, J. Low Temp. Phys. 87\, 205 (1992)
.\n[7] Y. Dubi\, Y. Meir\, and Y. Avishai\, Nature 449\, 876 (2007).\n[8]
E. Lucioni et al.\, in preparation\n\n//indico.ictp.it/event/a1113/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1113/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "A steady st
ate thermodynamic entanglement witness"\n\n
DTSTART;VALUE=DATE-TIME:20110203T103000Z
DTEND;VALUE=DATE-TIME:20110203T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1115@ictp.it
DESCRIPTION:We present a method for entanglement detection in steady state
systems using a thermodynamic witness. To illustrate\, we consider an ex
ample and find that for an XX spin chain\, the presence of an energy curre
nt increases the region of entanglement detected by the steady state witne
ss. Further\, we find that entanglement exists even at a high steady stat
e temperature. We also discuss concurrence in the steady state system and
find that the amount of entanglement can be increased by the current.\n\n
//indico.ictp.it/event/a1115/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1115/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Discrete parafermio
ns and critical interfaces in the Ashkin-Teller model"
DTSTART;VALUE=DATE-TIME:20110208T100000Z
DTEND;VALUE=DATE-TIME:20110208T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1116@ictp.it
DESCRIPTION:The Ashkin-Teller (AT) model is a 2D statistical model\, consi
sting of two coupled Ising models. It has a critical line with constant c
entral charge c=1 and varying critical exponents\, containing in particula
r the Z_4 spin model of Fateev-Zamolodchikov. We construct a discretely h
olomorphic parafermion existing for the whole critical line\, identify the
corresponding interface in terms of the cluster representation of the AT
model\, and find that this interface has a constant fractal dimension d_f=
3/2 along the critical line. In this talk\, I will explain this construct
ion and discuss attempts to relate the Z_N and AT interfaces to SLE. I wil
l also compare our results to recent works by M. Picco and R. Santachiara
(LPTHE/LPTMS\, Paris).\n\n- Y. Ikhlef\, M. A. Rajabpour\, J. Phys. A: Math
. Theor. 44 (2011) 042001\n\n//indico.ictp.it/event/a1116/
LOCATION:SISSA\, Santorio Bldg.\, room 129 1st floor
URL://indico.ictp.it/event/a1116/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on on Disorder and strong electron correlations: "Quasipar
ticles and the topological order of the \\nu=5/2 state"\n
DTSTART;VALUE=DATE-TIME:20110210T103000Z
DTEND;VALUE=DATE-TIME:20110210T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1121@ictp.it
DESCRIPTION:We present evidence supporting the weakly paired Moore-Read ph
ase in the half-filled second Landau level\, focusing on some of the *qual
itative* features of its excitations. Based on numerical studies\, we stu
dy both skyrmions and neutral excitations. Skyrmions are found to be pres
ent at low enough fields\, and are promoted by disorder [1]. We show that
systems with odd particle number at the flux N_\\phi=2N-3 can be interpret
ed as a neutral fermion mode of one unpaired fermion\, which is gapped. Th
e energetics of neutral fermions interacting with pairs of quasiparticles
is found to be in agreement with predictions for non-abelian statistics of
the Ising type with degenerate fusion channels 1 and \\psi [2]. In parti
cular\, we discuss signatures of the \\nu=5/2 Hall liquid in photoluminesc
ence (PL) experiments [3]: The neutral fermion mode is found to have two
distinct minima\, resulting in a double-peak structure in the PL spectrum
[2]. On the other hand\, a valence hole in proximity to the 2DEG induces
a disorder potential that locally favours skyrmions. Thus PL signals as a
probe for spin polarization in the groundstate should be interpreted cons
ervatively.\n\n[1] A. Wójs\, G. Möller\, S. H. Simon\, and N. R. Cooper\
, Phys. Rev. Lett. 104\, 086801 (2010).\n[2] G. Möller\, A. Wójs\, N. R.
Cooper\, arXiv:1009.4956.\n[3] Stern et al.\, Phys. Rev. Lett. 105\, 0968
01 (2010).\n\n//indico.ictp.it/event/a1121/
LOCATION:ICTP
URL://indico.ictp.it/event/a1121/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Many-body physics w
ith ultracold gases"
DTSTART;VALUE=DATE-TIME:20110215T103000Z
DTEND;VALUE=DATE-TIME:20110215T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1126@ictp.it
DESCRIPTION:In experiments performed with ultracold gases one can manipula
te the main parameters of the sample. This allows to induce various intri
guing quantum phenomena due to strong inter-particle correlations. In thi
s talk we review some recent quantum Monte Carlo studies of Fermi gases wi
th resonant inter-particle interactions. We discuss the properties of the
superfluid phase and of the exotic normal phase which can be stabilized a
t zero temperature by imposing an imbalance between the spin components.
For bosonic systems in optical lattices\, we investigate the superfluid to
insulator transition by using a novel continuous-space quantum Monte Carl
o technique. We address the regimes of strong inter-particle interactions
and weak or intermediate optical potentials\, thus extending previous the
oretical studies based on discrete lattice models.\n\n//indico.ictp.it/eve
nt/a1126/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1126/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Colloquium on Condensed Matter Physics:\n"Quantu
m physics in one dimension"
DTSTART;VALUE=DATE-TIME:20110216T150000Z
DTEND;VALUE=DATE-TIME:20110216T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1122@ictp.it
DESCRIPTION:The effect of interactions on quantum particles is a long stan
ding question\, with important consequences for most realistic systems. I
n one dimension interactions usually lead to a radically new type of physi
cs\, very different from the one we know for higher dimensional systems.\n
I will present the main concepts underlying this physics\, known as Luttin
ger liquids\, and show the various realizations of such systems that recen
t progress in material science\, nanotechnology and cold atomic physics ha
ve provided. I will discuss where the field is standing now\, and what ar
e today's challenges\, such as going beyond the Luttinger liquid concept.\
n\n//indico.ictp.it/event/a1122/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1122/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Spin dimers
: from BEC to Luttinger liquids"\n
DTSTART;VALUE=DATE-TIME:20110217T103000Z
DTEND;VALUE=DATE-TIME:20110217T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1129@ictp.it
DESCRIPTION:Localized spin systems\, and in particular dimer systems\, pro
vide a fantastic laboratory to study the interplay between quantum effects
and the interaction between excitations. Magnetic field and temperature
allow an excellent control on the density of excitations and various very
efficient probes such as neutrons and NMR are available. They can thus be
used as "quantum simulators'' to tackle with great success questions that
one would normally search in itinerant interacting quantum systems. In
particular they have provided excellent realizations of Bose-Einstein cond
ensates. This allowed not only to probe the properties of interacting bos
ons in a variety of dimensions but also to study in a controlled way addit
ional effects such as disorder. If the dimensionality is reduced they als
o allow to test in a quantitative way Luttinger liquid physics. I will di
scuss these various cases\, and show that we have now good theoretical too
ls to make quantitative comparisons with the experiments.\n\n//indico.ict
p.it/event/a1129/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1129/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar: "Through a structural phase transition in ion cha
ins: The inhomogeneous Kibble-Zurek mechanism"
DTSTART;VALUE=DATE-TIME:20110218T103000Z
DTEND;VALUE=DATE-TIME:20110218T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1128@ictp.it
DESCRIPTION:Structural defects in ion crystals can be formed during a line
ar quench of the transverse trapping frequency across the mechanical insta
bility from a linear chain to the zigzag structure. The density of defect
s after the sweep can be conveniently described by the Kibble-Zurek mechan
ism. In particular\, the number of kinks in the zigzag ordering can be de
rived from a time-dependent Ginzburg-Landau equation for the order paramet
er\, here the zigzag transverse size\, under the assumption that the ions
are continuously laser cooled. In a linear Paul trap the transition becom
es inhomogeneous\, the charge density being larger in the center and more
rarefied at the edges. During the linear quench the mechanical instabilit
y is first crossed in the center of the chain\, and a front\, at which the
mechanical instability is crossed during the quench\, is identified which
propagates along the chain from the center to the edges. If the velocity
of this front is smaller than the sound velocity\, the dynamics becomes a
diabatic even in the thermodynamic limit and no defect is produced. Other
wise\, the nucleation of kinks is reduced with respect to the case in whic
h the charges are homogeneously distributed\, leading to a new scaling of
the density of kinks with the quenching rate. The analytical predictions
are verified numerically by integrating the Langevin equations of motion o
f the ions\, in presence of a time-dependent transverse confinement. We a
rgue that the non-equilibrium dynamics of an ion chain in a Paul trap cons
titutes an ideal scenario to test the inhomogeneous extension of the Kibbl
e-Zurek mechanism\, which lacks experimental evidence to date.\n\nJournal-
refs:\nA. del Campo\, G. De Chiara\, G. Morigi\, M. B. Plenio\, A. Retzker
\, Phys. Rev. Lett. 105\, 075701 (2010)\n\nG. De Chiara\, A. del Campo\, G
. Morigi\, M. B. Plenio\, A. Retzker\, New J. Phys. 12\, 115003 (2010)\n\n
//indico.ictp.it/event/a1128/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1128/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "The free energy lan
dscape of cellular metabolism" \n
DTSTART;VALUE=DATE-TIME:20110222T100000Z
DTEND;VALUE=DATE-TIME:20110222T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1134@ictp.it
DESCRIPTION:A large part of a cell's energy budget is determined by the op
eration of its internal biochemical machinery\, or metabolism. Predicting
its behaviour at genome-scale (an issue with many important practical imp
lications) requires the computation of non-equilibrium steady states for r
eaction fluxes that integrate basic regulatory\, stoichiometric and thermo
dynamic constraints. The latter point is particularly delicate for a numbe
r of reasons. We describe the problem and some recent advances in the fie
ld that make use of both topological and dynamical aspects to reconstruct
the intracellular free energy landscape\, and (hopefully) improve the pred
ictive ability of existing schemes.\n\n//indico.ictp.it/event/a1134/
LOCATION:SISSA\, Santorio Bldg.\, Room 129 1st floor
URL://indico.ictp.it/event/a1134/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Multi-compo
nent fractional quantum Hall effect in graphene"\n\n
DTSTART;VALUE=DATE-TIME:20110224T103000Z
DTEND;VALUE=DATE-TIME:20110224T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1135@ictp.it
DESCRIPTION:A milestone in graphene research was the 2005 discovery of an
integer quantum Hall effect in this novel carbon-based two-dimensional (2D
) electron system. Contrary to its manifestation in conventional 2D elec
tron systems\, such as in semiconductor heterostructures\, the graphene q
uantum Hall effect reflects the "ultra-relativistic" character of the und
erlying carriers\, via a particular sequence of plateaus in the transvers
e Hall resistance.\nA natural question arises from this discovery: what ab
out the fractional quantum Hall effect in graphene? Does it also reflect
the ultra-relativistic character of the charge carriers? To what extent i
s it different from the fractional quantum Hall effect in (non-relativis
tic) semiconductor heterostructures? Many of these questions remain open
from an experimental point of view\, although some fractional states have
recently been observed in the two- and four-terminal configuration.\nThi
s talk aims at a theoretical perspective on the fractional quantum Hall e
ffect in graphene\, namely in view of its multi-component character due t
o the fourfold spin-valley degeneracy\, which is approximately respected b
y the underlying electron-electron interactions. This theoretical perspect
ive will be confronted with recent experimental advances.\n\n//indico.ict
p.it/event/a1135/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1135/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar: "On the uncertainty and positivity of Wigner fun
ctions of one-dimensional mixed states"
DTSTART;VALUE=DATE-TIME:20110225T103000Z
DTEND;VALUE=DATE-TIME:20110225T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1138@ictp.it
DESCRIPTION:We present a new uncertainty relation for one-dimensional mixe
d states given its purity and degree of non-Gaussianity. This relation ext
ends the purity-bounded uncertainty re\nlation for mixed states derived by
V. V. Dodonov and V. I. Man’ko. For the special case of pure states it
provides us with an extended version of the Robertson-Schrödinger uncerta
inty relation\, saturated by a set of states which includes all the eigens
tates of the quantum harmonic oscillator. We represent our results as a bo
und in a three-dimensional parametric space of mixed states and identify t
he regions of the bound realized by states with non- negative Wigner funct
ion. This takes us closer to a proper extension of Hudson’s theorem to m
ixed states and permits us to visualize and compare the set of states with
non-negative Wigner function and the set of states which minimize the new
ly derived uncertainty relation.\n\n//indico.ictp.it/event/a1138/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1138/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Diagrammatic Monte
Carlo for correlated fermions"\n
DTSTART;VALUE=DATE-TIME:20110301T103000Z
DTEND;VALUE=DATE-TIME:20110301T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1137@ictp.it
DESCRIPTION:One of the important goals promising a major impact on the fie
ld of condensed matter and far beyond\, is being able to describe properti
es of correlated fermionic systems quantitatively accurately without uncon
trolled approximations. In this talk\, I will focus on the family of diag
rammatic Monte Carlo (DiagMC) methods introduced recently to meet this cha
llenge. The Determinant DiagMC technique allowed to obtain the most accur
ate so far prediction of the critical temperature curve across the crossov
er from the Bardeen-Cooper-Schrieffer pairing to the Bose-Einstein condens
ate of molecules (the BCS-BEC crossover) in a two-component Fermi gas. A
new generation of DiagMC methods based on sampling irreducible Feynman dia
grams directly in the thermodynamic limit features an unprecedented tolera
nce to the notorious fermionic sign problem\, which makes it a promising t
echnique for unbiased solution of generic many-body fermionic systems. I
will substantiate this promise with accurate results for the repulsive Hub
bard model in the correlated Fermi liquid regime and a very recent calcula
tion of the equation of state of the unitary Fermi gas.\n\n//indico.ictp.i
t/event/a1137/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1137/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar: "Energy conversion and storage with nanomaterials
: Atomistic simulations"
DTSTART;VALUE=DATE-TIME:20110303T150000Z
DTEND;VALUE=DATE-TIME:20110303T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1140@ictp.it
DESCRIPTION:The capability of materials for energy conversion and storage
can be considerably extended by nanostructuring. The morphology and stabi
lity of a nanostructure depend crucially on the environmental conditions o
f fabrication and operation. It is therefore fundamental for energy appli
cations to understand in detail how the environment influences these prope
rties. In this talk\, I will discuss atomistic simulations based on densi
ty functional theory aimed at investigating the formation and stability of
nanostructures of oxides of platinum-group metals and of lithium in an ox
ygen-rich environment. These systems are relevant for fuel cells and lith
ium-air batteries\, respectively. I will show that the thermodynamics of
oxides is different when the nanoscopic size is taken into account and tha
t this has consequences for their functionality. I will thoroughly compar
e the calculations with experimental results on oxidation state\, morpholo
gy and functional behavior of nanostructures\, and I will discuss open que
stions and future developments.\n\n//indico.ictp.it/event/a1140/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1140/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Integer qua
ntum Hall edge states far from equilibrium"\n\n
DTSTART;VALUE=DATE-TIME:20110303T103000Z
DTEND;VALUE=DATE-TIME:20110303T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1143@ictp.it
DESCRIPTION:A non-equilibrium distribution of electrons is set up when two
quantum Hall edge states originating from sources at different potentials
meet at a quantum point contact. Recently\, several types of experiment
have probed the consequences of this non-equilibrium distribution\, first
in interferometers\, and recently by a direct measurement of the distribut
ion and its evolution with distance downstream from the quantum point cont
act [1].\nIn this talk I will describe theoretical work [2] aimed at under
standing aspects of these experiments.\n\nReferences\n\n[1] H. le Sueur\,
C. Altimiras\, U. Gennser\, A. Cavanna\, D. Mailly\, F. Pierre\, Phys. Rev
. Lett. 105\, 056803 (2010).\n\n[2] D. L. Kovrizhin and J. T. Chalker\, ar
Xiv:1009.4555\, and in preparation.\n\n//indico.ictp.it/event/a1143/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1143/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Efficient s
imulation of quantum-many-body systems with tensor networks"\n
DTSTART;VALUE=DATE-TIME:20110304T103000Z
DTEND;VALUE=DATE-TIME:20110304T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1141@ictp.it
DESCRIPTION:In this talk I will give a brief review on the intrinsic link
between the numerical renormalization group (NRG) and the density matrix r
enormalization group (DMRG) in terms of tensor networks. With respect to
the NRG then\, complete yet fully tractable many-body basis sets allow for
textbook evaluations of physical properties of quantum impurity models su
ch as dynamic correlation functions or quantum quenches. This\, for examp
le\, also provides a direct link to optical absorption spectra\, and provi
des a framework for a clean numerical treatment of Anderson orthogonality
exponents in the thermodynamic limit. More generally\, challenges in nume
rical complexity will be addressed\, highlighting a recent algorithmic adv
ance in terms of the generic implementation of non-abelian symmetries with
in tensor networks.\n\n//indico.ictp.it/event/a1141/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1141/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Colloquium on Condensed Matter: "Tuning lattice d
istortion by pressure: The insulator to metal transition and the onset o
f phase separated states"\n
DTSTART;VALUE=DATE-TIME:20110309T153000Z
DTEND;VALUE=DATE-TIME:20110309T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1145@ictp.it
DESCRIPTION:The experimental accessibility of high density phases in conde
nsed matter systems\, thanks to the advances of high pressure techniques o
ver the last years\, has switched pressure from being a less common extern
al perturbation probe into an increasingly versatile tool in materials res
earch. Here\, I want to focus on some selected pressure-induced effects i
n crystalline systems\, in particular on how the natural effect of promoti
ng more symmetric structure upon compressing the lattice can be worked out
into a tuning of local and extended lattice distortions arising from char
ge-lattice coupling. This is the exemplary case of the spontaneous symmet
ry breaking occurring in Jahn-Teller and Peierls systems. The physics of
these correlated materials is quite complex and typically characterized by
a delicate interplay among different interactions at the same energy scal
e. Applying pressure\, over even a relatively small range (0-40 GPa)\, ca
uses these systems to reach new\, and sometimes unconventional\, states bu
t it also enables to disentangle the effects of the different coupling mec
hanisms thus gaining a deeper knowledge of the ambient conditions phases.
As an example of a Jahn-Teller system I present an extended experimental
study of La-Ca manganites (La1-xCaxMnO3) under high pressure (range 0-30
GPa)\, with particular attention to the parent LaMnO3 compound and the LaM
n1-xGaxO3 family. Recent high pressure experiments (range 0-20 GPa) on se
veral Vanadium oxides with special focusing to the case of VO2 (Peierls sy
stem) is also discussed. We will see that\, apart from the characterizati
on of the new higher density phases\, the high pressure studies provide ke
y information on the physics of these systems at ambient pressure which st
imulates their theoretical modeling.\n\n//indico.ictp.it/event/a1145/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1145/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Aharonov-Bo
hm conductance through a single-channel quantum ring"\n\n
DTSTART;VALUE=DATE-TIME:20110310T103000Z
DTEND;VALUE=DATE-TIME:20110310T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1146@ictp.it
DESCRIPTION:We study the effect of electron-electron interaction on transp
ort through a tunnel-coupled single-channel ring. We find that the conduct
ance as a function of magnetic flux shows a series of interaction-induced
resonances that survive thermal averaging. The period of the series is gi
ven by the interaction strength alpha. The physics behind this behavior i
s the blocking of the tunneling current by the circular current. The main
mechanism of dephasing is due to circular-current fluctuations. The deph
asing rate is proportional to the tunneling rate and does not depend on al
pha.\n\n//indico.ictp.it/event/a1146/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1146/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "A field theory for fermi
onic ladder with generic intrachain interactions"\n\n
DTSTART;VALUE=DATE-TIME:20110314T100000Z
DTEND;VALUE=DATE-TIME:20110314T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1151@ictp.it
DESCRIPTION:An effective low energy field theory is developed for a system
of two chains. The main novelty of the approach is that it allows to tre
at generic intrachain repulsive interactions of arbitrary strength. The
chains are coupled by a direct tunneling and four-fermion interactions.
At low energies the individual chains are described as Luttinger liquids
with an arbitrary ratio of spin $v_s$ and charge $v_c$ velocities. A jud
icious choice of the basis for the decoupled chains greatly simplifies th
e description and allows one to separate high and low energy degrees of fr
eedom. In a direct analogy to the bulk cuprates the resulting effective f
ield theory distinguishes between three qualitatively different regimes:
(i) small doping ($v_c \n\n//indico.ictp.it/event/a1151/
LOCATION:SISSA\, Santorio Building\, Room 129 (1st floor)
URL://indico.ictp.it/event/a1151/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Statistical methods
in gene regulation"
DTSTART;VALUE=DATE-TIME:20110315T103000Z
DTEND;VALUE=DATE-TIME:20110315T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1152@ictp.it
DESCRIPTION:Gene regulation is one of the most interesting open problems i
n modern molecular biology. In this talk I will discuss in particular a c
lass of regulatory motifs known as "mixed feed forward loops (mFFLs)". Th
ese motifs seem to be under positive selection in the human regulatory net
work\, thus suggesting that they should play some important functional rol
e. Moreover\, in human\, several of the genes involved in these mFFLs are
known to be oncogenes (i.e. genes related to cancer progression). Our pr
oposal is that these mFFLs are used by the cell to keep under control the
stochastic fluctuations in the amount of proteins expressed by the target
genes and that for this reason their disregulation plays such an importan
t role in cancer progression. The talk will be divided in two parts. The
first will be devoted to a short pedagogical introduction to the organiza
tion of Eukaryotic genomes and to the mechanisms of gene regulation. Then
in the second part I will discuss\, using both stochastic equations and b
ioinformatic tools the role played by mFFLs in the regulatory network.\n\n
//indico.ictp.it/event/a1152/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1152/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: \n"Influenc
e of thermal fluctuations on the spectral function in 2D superconductors"\
n\n
DTSTART;VALUE=DATE-TIME:20110317T103000Z
DTEND;VALUE=DATE-TIME:20110317T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1154@ictp.it
DESCRIPTION:We study the behavior of single electron spectral function in
a model of 2D superconductors with strong phase fluctuations. It is shown
that in the limit when the gap amplitude is much smaller than the Fermi e
nergy the problem is equivalent to the anisotropic spin-1/2 Kondo model an
d some results can be obtained non-perturbatively.\n\n//indico.ictp.it/eve
nt/a1154/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1154/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Unusual singular be
haviour of the entanglement entropy in one dimension"
DTSTART;VALUE=DATE-TIME:20110322T100000Z
DTEND;VALUE=DATE-TIME:20110322T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1156@ictp.it
DESCRIPTION:We study the bipartite entanglement entropy for one-dimensiona
l systems. Its qualitative behavior is quite well understood: for gapped
systems the entropy saturates to a finite value\, while it diverges logari
thmically as the logarithm of the correlation length as one approaches a c
ritical\, conformal point of phase transition.\nUsing the example of two i
ntegrable models\, we argue that close to non-conformal points the entropy
shows a peculiar singular behavior\, characteristic of an essential singu
larity. At these non-conformal points the model undergoes a discontinuous
transition\, with a level crossing in the ground state and a quadratic exc
itation spectrum. We propose the entropy as an efficient tool to determin
e the discontinuous or continuous nature of a phase transition also in mor
e complicated models.\n\n- F. Franchini\, A. R. Its\, B.-Q. Jin\, V. E. Ko
repin\; J. Phys. A 40:8467 (2007)\n- F. Franchini\, A. R. Its\, V. E. Kore
pin\; J. Phys. A: Math. Theor. 41:025302 (2008)\n- F. Franchini\, E. Ercol
essi\, S. Evangelisti\, F. Ravanini\; Phys. Rev. B 83:012402 (2011)\n\n//i
ndico.ictp.it/event/a1156/
LOCATION:SISSA\, Santorio Bldg.\, Room 129
URL://indico.ictp.it/event/a1156/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Classical a
nd quantum critical behaviors in confined particle systems"\n\n
DTSTART;VALUE=DATE-TIME:20110324T103000Z
DTEND;VALUE=DATE-TIME:20110324T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1157@ictp.it
DESCRIPTION:Physical systems are generally inhomogeneneous\, while homogen
eous systems are often an ideal limit of experimental conditions. An impo
rtant issue of the theory of critical phenomena is how critical behaviors
develop in inhomogenous systems. Physically interesting systems are inter
acting particles confined within a limited region of space by an external
potential.\nRecent experiments of Bose-Einstein condensation in diluted at
omic vapors and of cold atoms in optical lattices are set up with a harmon
ic trap. They provide great opportunities to investigate the interplay be
tween quantum and statistical behaviors in particle systems\, and\, in par
ticular\, at the transitions between their thermodynamic and/or quantum ph
ases. Therefore\, a theoretical description of how criticality develops i
n the presence of the confining enternal field is of great importance for
these experiments.\nI present a trap-size scaling theory for confined part
icle systems at thermal and quantum transitions\, providing a framework to
describe the critical behaviors of confined particle systems. Some appli
cations to physically interesting models are discussed.\n\n//indico.ictp.i
t/event/a1157/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1157/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "The remanent densit
y of topological defects across a second order and \na Kosterlitz-Thoules
s transition"\n
DTSTART;VALUE=DATE-TIME:20110329T103000Z
DTEND;VALUE=DATE-TIME:20110329T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1159@ictp.it
DESCRIPTION:The state of a system taken through a phase transition is plag
ued with topological defects\, be them domain walls\, vortices\, monopoles
or other depending on the particular case at hand. After the quench thei
r spatial distribution changes and\, typically\, their density decreases.
The mechanisms whereby this occurs depend on the microscopic dynamics. R
ealizations of such “phase ordering kinetics” in condensed-matter are
manifold including the relaxation of vortices in planar magnets or monopol
es in magnetic spin-ice\, both thermally quenched. The characterization o
f the density of topological defects has also been of interest in cosmolog
y and the standard description in this context is given by the so-called K
ibble-Zurek mechanism. We have critically revisited this theory in two ch
aracteristic cases: a second order phase transition with discrete spontane
ous broken symmetry [1] and the Berezinsky-Kosterlitz-Thouless infinite or
der phase transition [2]. In this talk I shall explain our vision of this
problem.\n\n[1] Kibble-Zurek mechanism and infinitely slow annealing thro
ugh critical points\, G. Biroli\, L. F. Cugliandolo\, and A. Sicilia\, Phy
s. Rev. E 81\, 050101 (2010).\n[2] Quench dynamics of the 2d XY model\, A.
Jelic and L. F. Cugliandolo\, J. Stat. Mech. (2011) P02032\n\n//indico.ic
tp.it/event/a1159/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1159/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "The anomalo
us Curie-Weiss susceptibility of localized magnetic moments in 'relativis
tic' conductors"\n
DTSTART;VALUE=DATE-TIME:20110331T103000Z
DTEND;VALUE=DATE-TIME:20110331T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1160@ictp.it
DESCRIPTION:Localized magnetic moments randomly scattered on the surface o
f a two-dimensional conductor with quasi-relativistic electronic spectrum
are shown to exhibit a high-temperature susceptibility strongly deviating
from the Curie-Weiss law.\nThis effect is caused by the non-integrable sho
rt-distance singularity of the electron-mediated RKKY exchange between the
localized spins resulting in the failure of the standard mean-field theo
ry. A modification of the mean field theory resolving this problem is pro
posed and then applied to the experimentally interesting systems such as m
agnetic atoms on graphene and on the surfaces of topological insulators.\n
\n//indico.ictp.it/event/a1160/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1160/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Long range random corre
lations in individual spin glass samples"\n\n
DTSTART;VALUE=DATE-TIME:20110331T133000Z
DTEND;VALUE=DATE-TIME:20110331T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1162@ictp.it
DESCRIPTION:Various combinations of spin-spin correlations averaged over t
he randomness in spin glasses have long been known to be long-ranged\, tha
t is falling off like a power of the distance. This implies that correlati
ons must be long ranged in some sense already before averaging\, that is t
hey must be long ranged with finite probability also in individual samples
. The motivation for the study of correlations in individual samples of th
e paradigmatic case of spin glasses comes from the consideration that long
range correlations seem to be a common feature of several complex systems
\, and in some of the real life complex systems not only the averaged beha
viour\, but also the individual samples are important. Numerical simulatio
ns in the mean field model [1] have already showed that the distribution o
f the simplest spin-spin correlations is very broad at low temperatures. W
e performed similar studies on low dimensional (2d\,3d) spin glass samples
and found broad correlation distributions again. (In 2d there is no equil
ibrium spin glass phase\, but at low temperatures we found extremely long-
lived quasi-stable patterns that allowed us to measure the correlations.)
The dependence of the correlations on distance in Euclidean lattices is ra
ndom\, with anomalously large absolute values showing up with finite proba
bility even for large distances. The correlations extremely sensitively de
pend on the realization of the random couplings and on the boundary condit
ions\, but any averaging (over the randomness\, or over some spherical reg
ions around a reference site) washes away all this structure. The talk wil
l conclude with some speculations concerning the possible relevance of the
se findings to real life complex systems\, such as traffic\, electric powe
r\, or financial networks.\nReference [1] A. Billoire\, I. Kondor\, J. Luk
ic and E. Marinari: Large random correlations in individual mean field spi
n glass samples\, J. Stat. Mech. P02009 (2011)\n\n//indico.ictp.it/event/a
1162/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1162/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar:"Quantum stochastic p
rocesses: A case study"
DTSTART;VALUE=DATE-TIME:20110405T100000Z
DTEND;VALUE=DATE-TIME:20110405T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1163@ictp.it
DESCRIPTION:Quantum stochastic processes are tools to describe open and di
ssipative quantum systems. We shall discuss a simple down-to-earth model
of quantum stochastic process\, quantum analogue of the Brownian motion\,
whose definition is inspired by geometrical considerations but also by spe
culative dissipative phenomena in the quantum Hall effect.\n\n//indico.ict
p.it/event/a1163/
LOCATION:SISSA\, Santorio Bldg\, Room 129
URL://indico.ictp.it/event/a1163/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "The typical
states of a disordered Richardson model and many-body localization"\n
DTSTART;VALUE=DATE-TIME:20110407T103000Z
DTEND;VALUE=DATE-TIME:20110407T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1167@ictp.it
DESCRIPTION:We present a thorough numerical study of the Richardson model
with quenched disorder (a fully-connected XX-model with longitudinal rando
m fields). We find a relation between the inverse participation ratio\, t
he Edwards-Anderson order parameter and the average Hamming distance betwe
en spin configurations covered by a typical eigenstate for which we conjec
ture a remarkably simple form for the thermodynamic limit. We find a sudd
en onset of an exponentially large IPR on the space of spin configurations
\, although local observables (single-spin expectation values) never achie
ve thermalization. We also studied the random process defined by the spre
ad of a typical eigenstate on configuration space\, highlighting several s
imilarities with hopping on percolated hypercube\, a process used to mimic
the slow relaxation of spin glasses.\n\n//indico.ictp.it/event/a1167/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1167/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Functional renormal
ization group\, a novel approach to quantum field"\n
DTSTART;VALUE=DATE-TIME:20110412T103000Z
DTEND;VALUE=DATE-TIME:20110412T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1171@ictp.it
DESCRIPTION:The derivation of an exact equation describing the renormaliza
tion group flow of a scale dependent effective action\, know as effective
average action\, has opened the road to a new approach to quantum field t
heory. Through different examples ranging from second order phase transit
ions to quantum field theory on curved space\, we review the formalism an
d some techniques developed to solve the exact renormalization group flow
equation.\n\n//indico.ictp.it/event/a1171/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1171/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Functional renormal
ization group\, a novel approach to quantum field theory"\n
DTSTART;VALUE=DATE-TIME:20110412T103000Z
DTEND;VALUE=DATE-TIME:20110412T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1172@ictp.it
DESCRIPTION:The derivation of an exact equation describing the renormaliza
tion group flow of a scale dependent effective action\, know as effective
average action\, has opened the road to a new approach to quantum field t
heory. Through different examples ranging from second order phase transit
ions to quantum field theory on curved space\, we review the formalism an
d some techniques developed to solve the exact renormalization group flow
equation.\n\n//indico.ictp.it/event/a1172/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1172/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:\n"Enhancemen
t of superconductivity by Anderson localization"
DTSTART;VALUE=DATE-TIME:20110414T103000Z
DTEND;VALUE=DATE-TIME:20110414T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1173@ictp.it
DESCRIPTION:The influence of disorder on the temperature of the supercondu
cting transition (Tc) is studied within the sigma-model renormalization gr
oup framework. The electron-electron interaction in the particle-hole and
Cooper channels is taken into account and assumed to be short-range. Two
-dimensional systems in the weak localization and antilocalization regime\
, as well as systems near the mobility edge are considered. We show that
in all these regimes Anderson localization leads to a strong enhancement o
f Tc\, which is related to the multifractal character of wavefunctions.\n\
n//indico.ictp.it/event/a1173/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1173/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "On the criticality
of inferred models"
DTSTART;VALUE=DATE-TIME:20110419T100000Z
DTEND;VALUE=DATE-TIME:20110419T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1178@ictp.it
DESCRIPTION:Advanced inference techniques allow one to reconstruct the pat
tern of interaction from high dimensional data sets. We focus here on the
statistical properties of inferred models and argue that inference proced
ures are likely to yield models which are close to a phase transition. On
one side\, we show that the reparameterization invariant metrics in the s
pace of probability distributions of these models (the Fisher Information)
is directly related to the model's susceptibility. As a result\, disting
uishable models tend to accumulate close to critical points\, where the su
sceptibility diverges in infinite systems. On the other\, this region is
the one where the estimate of inferred parameters is most stable. In orde
r to illustrate these points\, we discuss inference of interacting point p
rocesses with application to financial data and show that sensible choices
of observation time-scales naturally yield models which are close to crit
icality.\n\n//indico.ictp.it/event/a1178/
LOCATION:SISSA\, Santorio Bldg\, Room 129
URL://indico.ictp.it/event/a1178/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"Bulk-bounda
ry correspondence of topological insulators"\n
DTSTART;VALUE=DATE-TIME:20110421T103000Z
DTEND;VALUE=DATE-TIME:20110421T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1177@ictp.it
DESCRIPTION:Topological insulators are noninteracting gapful fermionic sys
tems which have gapless boundary excitations. They are characterized by t
opological invariants. The topological invariants can be written in many
different ways\, including in terms of the Green’s functions. We show t
hat the existence of the boundary states directly follows\, and can be der
ived by simple manipulations\, from the existence of the bulk topological
invariant written in terms of the Green’s functions\, for all types of t
opological insulators in all spatial dimensions. At the same time\, the s
ame procedure explains why topological insulators\, once the interactions
are turned on\, can lose their boundary states.\n\n//indico.ictp.it/event/
a1177/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1177/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Colloquium on Condensed Matter Physics: "Quantum
quench in the transverse field ising chain "\n
DTSTART;VALUE=DATE-TIME:20110427T153000Z
DTEND;VALUE=DATE-TIME:20110427T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1184@ictp.it
DESCRIPTION:I consider the time evolution of observables in the transverse
field Ising chain (TFIC) after a sudden quench of the magnetic field. I
present exact analytical results for the asymptotic time and distance depe
ndence of one- and two-point correlation functions of the order parameter.
These results are based on two complementary approaches based on asympto
tic evaluations of determinants and form-factor sums. I show that the sta
tionary value of the two-point correlation function is not thermal\, but c
an be described by a generalized Gibbs ensemble (GGE). The approach to th
e stationary state can also be understood in terms of a GGE. Generalizatio
ns to particular quenches in other integrable models are discussed.\n\n//i
ndico.ictp.it/event/a1184/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1184/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Exciton-pol
aritons: An ultra-light dissipative Bose gas with tunable dimensionality"\
n
DTSTART;VALUE=DATE-TIME:20110428T140000Z
DTEND;VALUE=DATE-TIME:20110428T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1186@ictp.it
DESCRIPTION:Exciton-polaritons result from strong dipolar interaction betw
een excitons in a semiconductor material and the electromagnetic field con
fined in the same volume by a photonic nanostructure. A polariton gas is a
model system of a dissipative\, ultra-light Bose gas in a solid state env
ironment\, which provides an easy and complete experimental access to the
system observables. Thus\, fascinating phenomena like polariton lasing [1]
\, Bose-Einstein condensation [2] and more recently superfluidity [3] coul
d be demonstrated and studied with a great wealth of details. Recently\, o
wing to advances in the domain of semiconductor nanostructure fabrication\
, new interesting perspectives have emerged: the experimental realization
and study of a new state of Bose gases will soon be possible\, like low di
mensional Bose gases (1D quasi-condensate [4]\, Tonks-Girardeau liquids [5
])\, as well as room temperature quantum degeneracy. In this presentation\
, the most recent experimental observations on polariton gases will be rev
iewed\, and the future possible experimental realization with polariton co
ndensates will be discussed.\n\n[1] L. S. Dang et al.\, Phys. Rev. Lett.\,
81\, 3920 (1998) \n[2] J. Kasprzak et al.\, Nature 443\, 409 (2006) \n[3]
A. Amo et al.\, Nat Phys\, 5\, 805 (2009) \n[4] S. Richard et al.\, Phys.
Rev. Lett.\, 91\, 010405 (2003) \n[5] Kinoshita et al.\, Science\, 305\,
1125 (2004)\n\n//indico.ictp.it/event/a1186/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a1186/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR "Transport in pure an
d disordered spin chains"
DTSTART;VALUE=DATE-TIME:20110503T103000Z
DTEND;VALUE=DATE-TIME:20110503T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1190@ictp.it
DESCRIPTION:Spin chains represent interesting quantum many-body systems\,
well realized in several novel materials. Theoretical understanding of tra
nsport in clean and disordered spin chains will be reviewed in the talk. T
>0 spin stiffness will be discussed in connection with the integrability o
f the model. In particular\, the interplay of electron correlations and ra
ndom static disorder will be analysed with respect to possible many-body A
nderson localization. It will be shown that a single static impurity as we
ll as coupled impurity spins at T>0 lead to the incoherent transport with
a well defined current relaxation rate\, allowing also for either cutting
or healing effect\n\n//indico.ictp.it/event/a1190/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1190/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA COLLOQUIUM ON CONDENSED MATTER PHYSICS "The searc
h for Majorana fermions in topological superconductors"\n
DTSTART;VALUE=DATE-TIME:20110505T103000Z
DTEND;VALUE=DATE-TIME:20110505T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1191@ictp.it
DESCRIPTION:Majorana fermions (particles which are their own antiparticle)
may or may not exist in Nature as fundamental building blocks\, but in th
e solid state they can be constructed out of electron and hole excitations
. What is needed is a superconductor to hide the charge difference\, and a
topological phase to eliminate the zero-point motion that would cause an
energy difference. A qubit encoded in a pair of Majorana fermions is expec
ted to have an unusually long decoherence time. We will discuss strategies
to detect Majorana fermions in a topological superconductor\, as well as
possible applications in a quantum computer.\n\n//indico.ictp.it/event/a11
91/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1191/
END:VEVENT
BEGIN:VEVENT
SUMMARY:CONDENSED MATTER SEMINAR "First-principles simulations of chalcoge
nide phase-change materials"\n\n\n\n\n
DTSTART;VALUE=DATE-TIME:20110506T100000Z
DTEND;VALUE=DATE-TIME:20110506T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1193@ictp.it
DESCRIPTION:Phase-change materials based on chalcogenide alloys are used i
n rewritable optical media and are promising materials for non-volatile el
ectronic memories. Both types of devices are based on a) the ability of ph
ase-change materials to undergo reversible and fast transitions between th
e amorphous and crystalline phases upon heating by a laser or current puls
e and b) the strong optical and electronic contrast between the two phases
. In spite of their enormous technological importance\, the structural and
electronic properties of these materials and the mechanisms driving the t
ransitions are still controversial. In the first part of my talk I will pr
esent our computational study of the Raman spectrum of two prototypical ph
ase-change materials: GeTe and Ge2Sb2Te5. The spectrum of amorphous GeTe a
nd cubic and amorphous Ge2Sb2Te5 were obtained by ab initio simulations an
d empirical bond polarizability models. The models of the amorphous phases
of these systems were generated by quenching from the melt within ab init
io molecular dynamics. The calculated spectra are in good agreement with e
xperimental data and provide strong evidence of the existence of the pecul
iar local structures of the amorphous phase revealed by recent first-princ
iples simulations\, namely tetrahedral Ge and defective octahedral sites f
or a fraction of Ge and for all Sb and Te atoms. In the second part of my
talk I will present some preliminary results on two ongoing projects: a) t
he study of the crystallization kinetics in GeTe by ab initio molecular dy
namics combined with the metadynamics method and b) the investigation of t
he structural and magnetic properties of Ge2Sb2Te5 doped with magnetic imp
urities.\n.\n\n//indico.ictp.it/event/a1193/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1193/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Analogue Gravity in
Bose--Einstein Condensates"\n\n
DTSTART;VALUE=DATE-TIME:20110510T100000Z
DTEND;VALUE=DATE-TIME:20110510T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1197@ictp.it
DESCRIPTION:Under certain conditions\, the propagation of phonons in conde
nsed matter systems and the propagation of light in general relativity are
described by the same equation. However\, while quantum phenomena like th
e emission of thermal radiation from black holes are hardly detectable\, a
nalogue systems can provide the unique possibility to experimentally test
such effects. Originally driven by such motivation\, the study of analogie
s between quantum field theory in curved space and condensed matter has no
w produced a fruitful interchange leading to new and deep insights in both
fields. \n\nIn particular Bose-Einstein Condesates are a very rich and po
werful system in which this analogy can be implemented. I will give an ove
rview on how various issues in the context of general relativity can be a
ddressed through the analogy with BEC. Vice versa\, techniques imported f
rom general relativity can proficiently describe interesting phenomena in
BEC\, such as spontaneous phonon emission in flows crossing the speed of s
ound and resonant effects in system with multiple sonic points.\n\n//indic
o.ictp.it/event/a1197/
LOCATION:SISSA\, Room 129 1st Floor\, Santorio Building
URL://indico.ictp.it/event/a1197/
END:VEVENT
BEGIN:VEVENT
SUMMARY:JOINT ICTP/SISSA COLLOQUIUM ON CONDENSED MATTER PHYSICS: "Explorin
g the universe of protein structures beyond the Protein Data Bank"\n\n\n
DTSTART;VALUE=DATE-TIME:20110511T153000Z
DTEND;VALUE=DATE-TIME:20110511T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1195@ictp.it
DESCRIPTION:It is currently believed that the atlas of existing protein st
ructures is faithfully represented in the Protein Data Bank. However\, whe
ther this atlas covers the full universe of all possible protein structure
s is still a highly debated issue.\n\nBy using a sophisticated numerical a
pproach\, bias exchange metadynamics\, we performed an exhaustive explorat
ion of the conformational space of a 60 amino acid polypeptide chain descr
ibed with an accurate all-atom interaction potential. We generated a datab
ase of around 30\,000 compact folds with at least 30 % of secondary struct
ure and corresponding to local minima of the potential energy.\n\nThis ens
emble plausibly represents the universe of protein folds of similar length
\; indeed\, all the known folds are represented in the set with good accur
acy\, despite of the fact the simulation is performed for a homopeptide. H
owever\, we discover that the known folds form a rather small subset\, whi
ch cannot be reproduced by choosing random structures in the database. Rat
her\, natural and possible folds differ by the contact order\, on average
significantly smaller in the former. This suggests the presence of an evol
utionary bias\, possibly related to kinetic accessibility\, towards struct
ures with shorter loops between contacting residues.\n\n//indico.ictp.it/e
vent/a1195/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1195/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SEMINAR on Disorder and Strong Correlations: "Interaction effect
s in Dirac systems: driving chiral symmetry breaking?"
DTSTART;VALUE=DATE-TIME:20110512T103000Z
DTEND;VALUE=DATE-TIME:20110512T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1196@ictp.it
DESCRIPTION:We discuss interaction effects in Dirac materials. In a first
part I will discuss the role of interaction in graphene and manifestations
of interactions in transport measurements in weakly interacting systems.
For strong interactions for a concrete phenomenological model we will also
discuss the quantum critical conductivity of graphene at a semimetal-to-i
nsulator transition (breaking the chiral symmetry) and make connection to
experiments conducted on suspended graphene samples. In a second part we d
iscuss topological insulators and specifically the Dirac character of surf
ace states. We argue that upon driving a bulk quantum phase transition sur
face states can be tuned in a way which might facilitate the observation o
f chiral symmetry breaking on the surface.\n\n//indico.ictp.it/event/a1196
/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1196/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SEMINAR on Disorder and Strong Correlations: "Measurement backac
tion on adiabatic coherent electron transport"
DTSTART;VALUE=DATE-TIME:20110519T103000Z
DTEND;VALUE=DATE-TIME:20110519T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11105@ictp.it
DESCRIPTION:CTAP (coherent transport by adiabatic passage) is the spatial
analogue of STIRAP (stimulated Raman adiabatic passage). Its realization i
n nanostructures has potential applications for quantum information proces
sing. In this talk I discuss the backaction of measurement on electrons un
dergoing CTAP in a triple quantum dot system. Continuous measurement is ac
counted for using Korotkov's Bayesian quantum mechanics\, which allows to
study single realizations of the protocol while keeping track of the detec
tor output. One observes a trade off between information gain by the measu
rement vs. the fidelity of the protocol.\n\n//indico.ictp.it/event/a11105/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11105/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Periodic boundary condit
ion for a quantum integrable system with non-cubical configuration space
"\n
DTSTART;VALUE=DATE-TIME:20110617T103000Z
DTEND;VALUE=DATE-TIME:20110617T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11120@ictp.it
DESCRIPTION:Configuration spaces of some quantum integrable systems with s
ingular interactions can be determined by analysing the nature of such sin
gularity. In this talk\, we discuss how the interactions of spin Sutherla
nd model associated with the D_N type of root system lead to a Weyl-invari
ant configuration space\, which is a N-dimensional generalization of the r
hombic dodecahedron. Imposing periodic boundary condition on this nontriv
ial configuration space\, we derive the spectrum of spin Sutherland model
of D_N type. Applying the freezing trick\, subsequently we obtain an exac
t expression for the partition function of the related Haldane-Shastry typ
e spin chain.\n\nReferences: BBM\, Artemio González-López and Federico F
inkel\, Nucl. Phys. B 843 (2011) 505 and Nucl. Phys. B 812 (2009) 402.\n\n
//indico.ictp.it/event/a11120/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11120/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Chemical Physics: "Classical and quantum simul
ations in earth\, energy and environment systems"\n
DTSTART;VALUE=DATE-TIME:20110620T100000Z
DTEND;VALUE=DATE-TIME:20110620T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11122@ictp.it
DESCRIPTION:Recently\, we have applied the computational condensed matter
physics in liquid-liquid interface\, liquid-solid interface and the three
phase systems\, which we know little in comparison with the bulk condensed
matter materials & their surfaces\, and are important for earth\, energy
and environment systems. Of particular\, I’ll present three topics\, whi
ch are relevant to sedimentary Methane Hydrate (MH)\, CO2 Storage and Sequ
estration (CCS) and Enhanced Oil Recovery (EOR)\, respectively.\n(1) We ha
ve performed molecular dynamics simulations in order to investigate the st
ability of CH4- and CO2- hydrate. It was found that the cage occupancy of
hydrates influences the stability of the hydrates. More importantly\, the
actual three phase coexistence line of CO2 hydrate may be higher than the
value ever measured. Our results show that the “lowered” three phase c
oexistence line stemmed from the partial occupancy occurred during the lab
measurements.\n(2) We have investigated the contact angle of CO2/water/si
lica for two different silica surfaces by using large scale molecular dyna
mics simulations. It was found that the contact angle increases with press
ure for hydrophobic (siloxane) surface while almost constant for the hydro
philic (silanol) surface\, which is in excellent agreement with experiment
al observations. The difference results from the different interactions be
tween the CO2 thin film and silica surfaces.\n(3) By using first-principle
molecular dynamics\, we have studied the interface of new cleaved quartz
(0001) surface against liquid water at room temperature. It was found that
the quartz surface is not saturated as ideal geminal [Si-(OH)2] surface f
or all calculations. The rest Si-O* radicals\, presumably negatively charg
ed\, may help us solve a long-existing mystery in colloid and interface sc
iences\, that the silica surface is negatively charged at PH=7.\n\nIn coll
aboration with Yohei Mikami\, Shinya Tsuji\, Mia Ledyastuti\, Makoto Kunie
da and Toshifumi Matsuoka.\n\n//indico.ictp.it/event/a11122/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11122/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Colloquium on Condensed Matter Physics:\n"Common
ality and novelty of unconventional superconductors: \nCuO\, FeAs\, C60\,
organic and heavy-fermion systems"\n
DTSTART;VALUE=DATE-TIME:20110622T150000Z
DTEND;VALUE=DATE-TIME:20110622T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11121@ictp.it
DESCRIPTION:The year 2011 marks the 100th year anniversary of the discover
y of superconductivity by Kammerlingh Onnes. Since then\, superconductivit
y of simple metals\, such as Al\, Sn\, and Hg\, was explained by the BCS t
heory more than 50 years ago. The BCS theory has several key features: (a)
pairing mediated by phonons\; (b) energy scale of condensing charges\, i.
e.\, Fermi energy E_F\, being much larger than that of mediating fluctuati
ons hw_B (phonon frequency)\; (c) the transition temperature Tc scales wit
h hw_B without directly depending on the carrier density.\nDuring recent 3
0 years\, several new superconductors have been discovered: they include h
igh- Tc cuprates\, organic BEDT\, alkali-doped A3C60\, heavy-fermion\, and
FeAs superconductors which were discovered about three years ago. These s
ystems are much different from BCS superconductors in: (a) pairing seems t
o be mediated by the spin fluctuations rather than lattice vibrations\; (b
) effective energy scales of superconducting charges are comparable with e
nergy scales of spin fluctuations\, indicating non-retarded interaction\;
and (c) the transition temperature scales with the superfluid density n_s/
m* which represents the charge energy\, suggesting relevance of Bose-Eins
tein condensation of pre-formed pairs.\nIn this talk\, I will demonstrate
striking commonalities of these new unconventional superconductors by show
ing accumulated experimental results on energy scales and phase diagrams f
rom muon spin relaxation (MuSR)\, neutron scattering\, specific heat\, and
other measurements\, and discuss their implications on pairing and conden
sation mechanisms. Especially\, I will elucidate important roles of collec
tive soft modes relevant to competing states in determining Tc\, and advan
tage of possible resonance of the two key energy scales\, E_F\, for charge
s and hw_B for spins\, in the process of crossover from Bose Einstein to B
CS condensation for the pairing mediated by spin fluctuations.\nReferences
:\nY.J. Uemura\, Nature Materials 8 (2009) 253-255. \nY.J. Uemura\, Physic
a B404 (2009) 3195-3201.\n\n//indico.ictp.it/event/a11121/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11121/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on statistical physics: "Symmetry and the dynamic
s and evolution of Boolean networks"
DTSTART;VALUE=DATE-TIME:20110628T103000Z
DTEND;VALUE=DATE-TIME:20110628T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11125@ictp.it
DESCRIPTION:The concept of symmetry has played a fundamental role in many
of the advances of theoretical physics over the last century. In the physi
cs of complex networks\, symmetry also plays an important role. This talk
will explore one way that symmetry can be used in Network Science. It will
consider Boolean networks\, which are simple models of genetic regulatory
systems\, as well as of a variety of physical\, social\, and economic sys
tems. They consist of a directed graph with nodes that have binary output
states that are heterogeneous functions of the binary input they receive.
Each node receives input only from the nodes connected to it by the in‐l
inks of the graph. In general there is a symmetry associated with the dyna
mics Boolean networks\, and different dynamics are characterized by differ
ent symmetries. Furthermore\, if the networks are evolving then they refle
ct the symmetry of their evolutionary dynamics. Computer simulations\, ana
lytic statistical mechanics\, and group theoretic methods will be used to
identify the symmetry and to use the results to distinguish various networ
k dynamics. Important symmetry groups will be identified. These groups inc
lude the canalization preserving group. Canalization is a form of network
robustness that is important for developmental biological systems.\nRecent
advances in direct construction methods for sampling graphs with arbitrar
y given degree sequence and the discovery of graphicality transitions in s
cale‐free networks will also be discussed.\n\n//indico.ictp.it/event/a11
125/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11125/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar: "Kondo transport in nanocontact systems under bi
as"
DTSTART;VALUE=DATE-TIME:20110628T150000Z
DTEND;VALUE=DATE-TIME:20110628T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11128@ictp.it
DESCRIPTION:Kondo transport in a two-electrode mesoscopic system under bia
s has unique properties because of two electron reservoirs and applied bia
s. The former yields two tunneling levels in addition to the Kondo peak a
t the Fermi level and the latter causes quasiparticle resonant tunneling w
hen the chemical potential of one reservoir reaches the tunneling level.
Various lineshapes of nonlinear conductance observed in a quantum point co
ntact\, scanning tunneling microscopy on a magnetic atom adsorbed on a met
allic substrate\, and a single-electron transistor with a quantum dot\, wh
ich are not fully understood yet\, can be explained by the quasiparticle t
unneling through the abovementioned tunneling levels. I present novel Gre
en's function technique to obtain the spectral function for a given bias.\
n\n//indico.ictp.it/event/a11128/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a11128/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Entropy of network ense
mbles"\n
DTSTART;VALUE=DATE-TIME:20110706T100000Z
DTEND;VALUE=DATE-TIME:20110706T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11135@ictp.it
DESCRIPTION:The quantification of the complexity of networks is\, today\,
a fundamental problem in the physics of complex systems. A possible roadm
ap to solve the problem is via extending key concepts of information theor
y to networks. In this talk we discuss recent works defining the Shannon
entropy of a network ensemble and evaluating how it relates to the Gibbs a
nd von Neumann entropies of network ensembles. The quantities we introduc
e here play a crucial role for the formulation of null models of networks
through maximum-entropy arguments and contribute to inference problems e
merging in the field of complex networks.\n\n//indico.ictp.it/event/a11135
/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a11135/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "DNA knotting inside vir
al capsids: A computational approach"\n
DTSTART;VALUE=DATE-TIME:20110713T153000Z
DTEND;VALUE=DATE-TIME:20110713T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11140@ictp.it
DESCRIPTION:The packing of DNA inside bacteriophages arguably yields the s
implest example of genome organisation in living organisms [1\, 2]. An ind
irect indication of how DNA is packaged is provided by the detected spectr
um of knots formed by DNA that is circularised inside the P4 viral capsid
[3\, 4].\nThe experimental results on the knot spectrum of the P4 DNA are
here compared to results of coarse-grained simulation of DNA knotting in c
onfined volumes. We start by considering a standard coarse-grained model f
or DNA which is known to be capable of reproducing the salient physical as
pects of free\, unconstrained DNA [5]. Specifically the model accounts for
DNA bending rigidity and excluded volume interactions. By subjecting the
model DNA molecules to spatial confinement it is found that confinement fa
vours chiral knots over achiral ones\, in agreement with P4 experiments.
However\, no significant bias of torus over twist knots is found\, contrar
y to what found in P4 experiments [6\, 7]. A good agreement with experimen
t is found\, instead\, upon introducing an additional interaction potentia
l that accounts for tendency of contacting DNA portions to order as in cho
lesteric liquid crystals.\nAccounting for this local potential allows us t
o reproduce the main experimental data on DNA organisation in phages\, inc
luding the cryo-EM observations and detailed features of the spectrum of D
NA knots formed inside viral capsids. The DNA knots we observe are strongl
y delocalized and\, intriguingly\, this is shown not to interfere with gen
ome ejection out of the phage [8].\n\nIf time allows I will report on rece
nt characterizations of evolutionary aspects that have arguably lead to th
e appearance of knots in naturally-occurring proteins[9].\n\nReferences\n[
1] Earnshaw WC\, Harrison SC (1977) DNA arrangement in isometric phage hea
ds. Nature 268:598-602.\n[2] Gelbart WM\, Knobler CM (2009) Virology. pres
surized viruses. Science 323:1682-1683.\n[3] Arsuaga J\, Vazquez M\, Trigu
eros S\, Sumners D\, Roca J (2002) Proc Natl Acad Sci U S A 99:5373-5377.\
n[4] Arsuaga\, J et al. (2005) Proc Natl Acad Sci U S A 102:9165-9169.\n[5
] Rybenkov VV\, Cozzarelli NR\, Vologodskii AV (1993) Proc Natl Acad Sci U
S A 90:5307-5311.\n[6] Micheletti C\, Marenduzzo D\, Orlandini E\, Sumner
s DW (2006) J Chem Phys 124:64903-64903.\n[7] Micheletti C\, Marenduzzo D\
, Orlandini E\, Sumners DW (2008) Biophys J 95:3591-3599.\n[8] Marenduzzo
D\, Orlandini E\, Stasiak A\, Sumners DW\, Tubiana L\, Micheletti C (2009)
Proc Natl Acad Sci U S A 106:22269-22274. \n[9] Potestio\, R\, Micheletti
C. and Orl\n\n//indico.ictp.it/event/a11140/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11140/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Accelerated sampling of
the conformational space in biomolecules: From small proteins to RNAs"\n
DTSTART;VALUE=DATE-TIME:20110715T150000Z
DTEND;VALUE=DATE-TIME:20110715T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11143@ictp.it
DESCRIPTION:Recently developed free-energy methods (steered molecular dyna
mics\, well-tempered metadynamics\, parallel tempering and solute temperin
g) will be discussed\, and their application to the folding of small prote
ins and RNA molecules will be shown. Using these techniques\, a proposed
model for RNA unwinding is validated and interpreted at atomistic resoluti
on.\n\n//indico.ictp.it/event/a11143/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11143/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics:"Information transmission
in small gene regulatory networks"\n
DTSTART;VALUE=DATE-TIME:20110718T153000Z
DTEND;VALUE=DATE-TIME:20110718T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11144@ictp.it
DESCRIPTION:Many of the biological networks inside cells can be thought of
as transmitting information from the inputs (e.g.\, the concentrations of
transcription factors or other signaling molecules) to their outputs (e.g
.\, the expression levels of various genes). On the molecular level\, the
relatively small concentrations of the relevant molecules and the intrinsi
c randomness of chemical reactions provide sources of noise that set physi
cal limits on this information transmission. Given these limits\, not all
networks perform equally well\, and maximizing information transmission pr
ovides a optimization principle from which we might hope to derive the pro
perties of real regulatory networks. Inspired by the precision of transmis
sion of positional information in the early development of the fly embryo\
, I will discuss the properties of specific small networks that can transm
it the maximum information. Concretely\, I will show how the form of molec
ular noise drives predictions not just of the qualitative network topology
but also the quantitative parameters for the input/output relations at th
e nodes of the network. I will show how the molecular details of regulatio
n change the networks ability to transmit information.\n\n//indico.ictp.it
/event/a11144/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11144/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "The other side of genome
s: When non-coding is functional and coding is not"\n
DTSTART;VALUE=DATE-TIME:20110719T103000Z
DTEND;VALUE=DATE-TIME:20110719T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11145@ictp.it
DESCRIPTION:We have recently developed a powerful algorithm to predict pro
tein-RNA associations that we validate using a series of assays including
immunoprecipitation of protein-RNA complexes. At the same time\, we work
on the prediction of interactomes of amyloid fibrils in the cellular conte
xt and develop models for calculating the interaction potential with mole
cular chaperones. A series of bioinformatics tools to predict toxicity un
der a variety of experimental conditions will be presented.\n\n//indico.ic
tp.it/event/a11145/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11145/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "How cells can improve th
eir sensitivity to concentration changes"
DTSTART;VALUE=DATE-TIME:20110720T153000Z
DTEND;VALUE=DATE-TIME:20110720T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11146@ictp.it
DESCRIPTION:Molecule concentrations are the building blocks of information
transmission in living organisms. Thanks to their molecule receptors\, c
ells are able to sense concentration gradients with high accuracy. For ex
ample\, small motile bacteria such as E. coli detect spatial gradients ind
irectly by measuring concentration ramps (temporal concentration changes)
as they swim\, and can respond to concentrations as low as 3.2 nM - about
three molecules per cell volume. The noise arising from the small number
of detected molecules sets a fundamental physical limit on the accuracy of
concentration sensing\, as originally shown in the seminal work of Berg a
nd Purcell\, but up to now no theory existed for the physical limit of ram
p sensing\, which is what bacteria actually do. I will show how such a bo
und can be derived for different measurement devices\, from a single recep
tor to an entire cell. I will then present a plausible implementation of t
hat bound by a realistic (bio)chemical network\, similar to the adaptation
system of E. coli. Finally I will show how energy consumption at the lev
el of the receptors can be used to increase the accuracy by a twofold fact
or over a passive scheme where no energy is consumed.\n\n//indico.ictp.it/
event/a11146/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11146/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter seminar: "Correlated tunneling
in hydrogen bonds"
DTSTART;VALUE=DATE-TIME:20110726T140000Z
DTEND;VALUE=DATE-TIME:20110726T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11222@ictp.it
DESCRIPTION:The momentum distribution of the protons participating in hydr
ogen bonds in water and ice deviates considerably from the classical equil
ibrium distribution. As a consequence the molecular structure of water and
ice is directly affected by quantum mechanics. Yet the effect is essentia
lly quasi-harmonic and quasi-classical in nature. New physics occurs in pr
esence of proton tunneling\, which is collective and dominated by strong l
ocal correlations. These effects will be discussed with special reference
to the transition from ice VIII to ice VII\, which is driven by quantum fl
uctuations under appropriate temperature an d pressure conditions.\n\n//in
dico.ictp.it/event/a11222/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a11222/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Searching for needles in
haystacks (Thinking about fast evolutionary processes through nextgen seq
uencing of tumors)"\n
DTSTART;VALUE=DATE-TIME:20110726T103000Z
DTEND;VALUE=DATE-TIME:20110726T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11223@ictp.it
DESCRIPTION://indico.ictp.it/event/a11223/
LOCATION:ICTP Leonardo da Vinci Building Seminar Room
URL://indico.ictp.it/event/a11223/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar: "Y-junction of quantum wires: Fixed points struc
ture and conductances"\n
DTSTART;VALUE=DATE-TIME:20110802T103000Z
DTEND;VALUE=DATE-TIME:20110802T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11225@ictp.it
DESCRIPTION:The transport properties of three Luttinger liquid wires (with
possibly different interaction strength)\, connected through a Y-junction
\, are studied within the scattering state formalism. The case of a symme
tric set-up without magnetic flux is considered first\, for which the scat
tering matrix and the matrix of conductances is parametrized by two variab
les. For these we derive coupled RG equations\, with one-loop contributio
ns summed to infinite order of bulk interaction. The Y-junction pierced by
magnetic flux is similarly described by three coupled RG equations. The f
ixed point structure and and the implicit solution of these equations is p
resented. For sufficiently strong attractive interaction new fixed points
are found.\n\n//indico.ictp.it/event/a11225/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11225/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "From systems biology to
synthetic ecology"\n
DTSTART;VALUE=DATE-TIME:20110816T103000Z
DTEND;VALUE=DATE-TIME:20110816T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11230@ictp.it
DESCRIPTION:Cellular metabolism consists of a complex network of chemical
reactions\, which provide the cell with a reliable supply of energy and bu
ilding blocks. Optimization approaches based on steady state approximatio
ns have been increasingly successful at predicting how individual microbia
l species allocate available resources under different environments and pe
rturbations. Possible extensions of current approaches that incorporate i
nteractions between different species can help understand natural microbia
l ecosystems and engineer artificial ones\, with applications ranging from
metabolic engineering to the human microbiome.\n\n//indico.ictp.it/event/
a11230/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11230/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar: " Fermi distribution of Fermi-surf "
DTSTART;VALUE=DATE-TIME:20110912T103000Z
DTEND;VALUE=DATE-TIME:20110912T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11248@ictp.it
DESCRIPTION:When a classical device suddenly perturbs a degenerate Fermi g
as a coherent Fermi state arises. Coherent Fermi states involve an infinit
e superposition of particles and holes arranged in such a manner that ther
e are no holes in the Fermi sea but the Fermi level depends on time and sp
ace - a Fermi-surf.\nFermi distribution and other features of a Fermi-sur
f has a universal nature. It is described by Airy functions regardless of
details of a perturbation.\n\n//indico.ictp.it/event/a11248/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11248/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Universal s
tatistics for directed polymers and the KPZ equation from the replica Beth
e Ansatz"\n
DTSTART;VALUE=DATE-TIME:20110915T103000Z
DTEND;VALUE=DATE-TIME:20110915T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11251@ictp.it
DESCRIPTION:I will first review the problem of the directed polymer (DP) i
n a random potential and of the Kardar Parisi Zhang (KPZ) growth equation\
, and their mutual relation. I will introduce the replica Bethe Ansatz me
thod and how it has allowed us to obtain the distribution of the free ener
gy of the DP and of the height field of the KPZ equation. For large polym
er size (large KPZ time) this distribution converges to the Tracy Widom di
stribution of the largest eigenvalue of a gaussian random matrix. I will
discuss our results for both fixed and free endpoints corresponding to gro
wth from a droplet or from an initially flat interface.\n\n//indico.ictp.i
t/event/a11251/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11251/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Scattering properties of
ground states in the 3-d random-field Ising model"\n
DTSTART;VALUE=DATE-TIME:20111007T093000Z
DTEND;VALUE=DATE-TIME:20111007T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11263@ictp.it
DESCRIPTION:We study the ground-state (T = 0) morphologies in the d = 3 ra
ndom-field Ising model (RFIM) using a computationally efficient graph-cut
method. We focus on ground states which arise for disorder strengths lower
or higher than the critical disorder strength at T = 0. These states cons
ist of correlated “domains” of up and down spins which are separated b
y rough\, fractal interfaces. They show novel scattering properties with a
cusp singularity in the correlation function at short distances.\n\n//ind
ico.ictp.it/event/a11263/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11263/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Coset graphs in log
arithmic minimal models"
DTSTART;VALUE=DATE-TIME:20111018T100000Z
DTEND;VALUE=DATE-TIME:20111018T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11274@ictp.it
DESCRIPTION:An overview is given of the logarithmic minimal models as prot
otypical examples of logarithmic CFTs. In the boundary theory\, multiplic
ation in the Grothendieck ring of W-projective representations leads to a
Verlinde-like formula involving A-type twisted affine graphs and their cos
et graphs.\nThis provides compact formulas for the conformal partition fun
ctions with W-projective boundary conditions. On the torus\, modular invar
iant partition functions are proposed as sesquilinear forms in W-projectiv
e and rational minimal characters that are encoded by the same coset fusio
n graphs.\n\n//indico.ictp.it/event/a11274/
LOCATION:SISSA\, Santorio Bldg.\, Room 108 (1st floor)
URL://indico.ictp.it/event/a11274/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar: " XXZ Spin-1/2 chain representation of the one-d
imensional Bose-Hubbard model at half-filling "\n
DTSTART;VALUE=DATE-TIME:20111019T150000Z
DTEND;VALUE=DATE-TIME:20111019T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11278@ictp.it
DESCRIPTION:We apply a general technique\, based on the similarity renorma
lization procedure introduced by Glazek and Wilson\, to investigate the st
rong coupling expansion of the Bose-Hubbard model at half filling. This ap
proach provides a mapping of the Bose-Hubbard model onto an XXZ spin-1/2 m
agnetic chain\, with renormalized exchange energy J and renormalized anis
otropy parameter Delta. We then exploit the analytical results availabl
e for the spin-1/2 XXZ model in a finite chain of length N to compute the
correlation functions of the Bose-Hubbard model and to compare them with t
hose obtained from the numerical density matrix renormalization group appr
oach\; the agreement is very good\, even at N = 30. Our approach allows t
o engineer a reliable quantum magnetic analog of the Bose-Hubbard model\,
enabling us to show that the superfluid-charge density wave (superfluid-Mo
tt insulator) phase transition of the Bose-Hubbard model corresponds\,
for Delta =1 (Delta =-1) to the spin liquid-antiferromagnet (spin liquid-
ferromagnet) phase transition of the XXZ-model.\n\n[with the collaboratio
n of P. Sodano (Università di Perugia)\, D. Rossini (SNS-Pisa)\, A. Tromb
ettoni (SISSA)]\n\n//indico.ictp.it/event/a11278/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11278/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Identifying
the critical state of the Anderson localization transition with its multi
fractality"\n
DTSTART;VALUE=DATE-TIME:20111020T103000Z
DTEND;VALUE=DATE-TIME:20111020T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11280@ictp.it
DESCRIPTION:Anderson localization is a metal-insulator transition caused b
y disorder. It has been connected to several phenomena such as conductivit
y of solids\, transport of light and sound in random media\, and the quant
um Hall transition. The scaling theory of localization predicts that all
states are localized in 1D and 2D disordered systems. In 3D there exists
a transition point where the eigenstates are critical and have multifracta
l structure. I report how this multifractality has recently been observed
in the Anderson transition of ultrasound in a 3D metal network. Furtherm
ore\, using analytic calculations and numerical simulations\, I show that
the propagation of electromagnetic polar waves in a 1D array of near-reson
ant scatterers also follows critical scaling behavior. This is caused by
the long-range interaction between the scatterers\, which is not treated b
y the scaling theory.\n\n//indico.ictp.it/event/a11280/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11280/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Localization and gl
assy dynamics of many-body quantum systems"\n
DTSTART;VALUE=DATE-TIME:20111025T100000Z
DTEND;VALUE=DATE-TIME:20111025T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11282@ictp.it
DESCRIPTION:When classical systems fail to explore their entire configurat
ionalspace\, intriguing macroscopicphenomena like aging and glass formatio
n may emerge. Also closed quanto-mechanical systems may stop wandering fre
ely around the whole Hilbert space\, even if they are initially prepared i
nto a macroscopically large combination of eigenstates. This phenomenon i
s actually known to occur in presence of disorder and manifests itself eit
her by\nsingle-particle [1] or many-particle [2] wavefunction localizatio
n. However\, alike classical models for glassy behavior\, ergodicity break
down may not necessarily require disorder. [3] In this talk I will report
numerical evidences that the dynamics of strongly interacting lattice bos
ons driven sufficiently far from equilibrium can be trapped into extremely
long-lived inhomogeneous metastable states. [4] The slowing down of inco
herent density excitations above a threshold energy\, much reminiscent of
a dynamical arrest on the verge of a glass transition\, is identified as t
he key feature of this phenomenon. We argue that the resulting long-lived
inhomogeneities are responsible for the lack of thermalization observed i
n large systems. [5] Such a rich phenomenology could be experimentally un
covered upon probing the out-of-equilibrium dynamics of conveniently prepa
red quantum states of trapped cold atoms which I will discuss. The approa
ch used to extensively investigate this phenomenon is based both on the ex
act solution of the quantum dynamics and on a novel real- time variational
Quantum Monte Carlo method we have introduced. [4] The latter approach o
ffers a reliable accuracy and stability in the study of 1-dimensional syst
ems while also o_ering a seamless exploration of higher dimensional geomet
ries.\nREFERENCES\n[1] P. W. Anderson\, Phys. Rev. 109\, 1492 (1958).\n[2]
D. Basko\, I. Aleiner and B. Altshuler\, Annals of Physics 321\,1126 (200
6)\n[3] G. Biroli and M. Mezard Phys. Rev. Lett. 88\, 025501 (2001).\n[4]
G. Carleo\, F. Becca\, M. Schiro and M. Fabrizio\, arXiv:1109.2516 (2011).
\n[5] C. Kollath\, A. M. Lauchli and E. Altman\, Phys. Rev. Lett. 98\, 180
601 (2007).\n\n//indico.ictp.it/event/a11282/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11282/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Mean field theory f
or nonequilibrium network reconstruction"\n
DTSTART;VALUE=DATE-TIME:20111025T130000Z
DTEND;VALUE=DATE-TIME:20111025T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11283@ictp.it
DESCRIPTION:With the advancement of recording technology in various parts
of biology\, we can now observe many elements in a biological system at th
e same time. For instance we can measure the expression level of many gen
es using gene microarrays or spike trains from many neurons using multi-el
ectrode arrays. Given this\, an important and interesting question to ask
is "can we use such data to infer interactions between elements of the sy
stem?". In this talk\, I will describe toy versions of this problem. I w
ill briefly describe how it can be done for an equilibrium Ising model\, t
hat is the inverse Ising problem\; then I discuss inferring the interactio
ns of a non-equilibrium Sherrington-Kirkpatrick model showing how Dynamica
l Mean-Field theory (naive mean field\, TAP and exact MF) can be developed
and exploited for inferring network connectivity.\n\n//indico.ictp.it/eve
nt/a11283/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11283/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Local spect
roscopies and percolating transport in quantum Hall systems: Theory and ex
periment"\n
DTSTART;VALUE=DATE-TIME:20111027T103000Z
DTEND;VALUE=DATE-TIME:20111027T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11287@ictp.it
DESCRIPTION:Recent advances in high resolution scanning tunneling spectros
copy of disordered two-dimensional electron systems under high magnetic fi
eld will be the starting point for theoretical developments aiming at a qu
antum description of guiding center motion of the usual cyclotron orbits.
The emphasis will be put on real-space imaging of Landau states and the d
escription of some new observables\, such as two-point correlations of den
sity of states in the quantum Hall regime.\nIn a second part of the talk\,
macroscopic transport will be studied theoretically in a high temperature
range where the classical percolation of drift states dominates. Crossove
r functions are obtained\, which allow the extraction of critical exponent
from recent conductivity measurements.\n\n//indico.ictp.it/event/a11287/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11287/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Edge properties and
the absolute value of the topological angle"\n
DTSTART;VALUE=DATE-TIME:20111108T103000Z
DTEND;VALUE=DATE-TIME:20111108T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11293@ictp.it
DESCRIPTION:I will discuss the role of the absolute value (that is\, not m
odulo 2\\pi) of the topological angle in conformal sigma models. This will
be applied to the spin quantum Hall (class C) problem\, where I will show
that the different plateaus exhibit different transport properties due to
the presence of extra edge states.\n\n//indico.ictp.it/event/a11293/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11293/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: " What are t
he relevant disorder scales for quantum transport in graphene? "
DTSTART;VALUE=DATE-TIME:20111110T103000Z
DTEND;VALUE=DATE-TIME:20111110T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11288@ictp.it
DESCRIPTION:Since the very first investigations of the electronic properti
es of graphene the nature of the scattering disorder potential has been
shown to play an essential role in determining the carrier density depen
dence of the conductance. Impurity scattering is characterized by two diff
erent times the transport and elastic scattering times which are sensitiv
e to the linear energy dispersion of graphene. The analysis of the ratio
between these two times gives insight on the nature (neutral or charged)
and range of the scatterers. We discuss how to extract these two times
from magneto-transport measurements and analyze their differences in mono
layer and bilayer Graphene in relation with the different symmetry propert
ies of their band structure and wave functions. We show that whereas short
range impurity scattering is the dominant mechanism limiting the classica
l transport\, phase coherent mesoscopic transport is very sensitive to lo
ng range disorder. In particular\, the formation of electron/hole puddles
in the vicinity of the charge neutrality point strongly affects the ampl
itude of the conductance fluctuations and the induced supercurrent in the
presence of superconducting electrodes.\n\n//indico.ictp.it/event/a11288/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11288/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sasha Gogolin Memorial Meeting
DTSTART;VALUE=DATE-TIME:20111110T083000Z
DTEND;VALUE=DATE-TIME:20111111T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11295@ictp.it
DESCRIPTION:Detailed programme of the event is available here\n\n//indico.
ictp.it/event/a11295/
LOCATION:ICTP Adriatico Guest House Denardo Lecture Hall
URL://indico.ictp.it/event/a11295/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sasha Gogolin Memorial Meeting
DTSTART;VALUE=DATE-TIME:20111111T083000Z
DTEND;VALUE=DATE-TIME:20111111T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11296@ictp.it
DESCRIPTION:11 November: from 9:30 to 17:00\, detailed programme of the ev
ent is available here\n\n//indico.ictp.it/event/a11296/
LOCATION:ICTP Adriatico Guest House Denardo Lecture Hall
URL://indico.ictp.it/event/a11296/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "The inverse Ising p
roblem for one-dimensional chains with arbitrary finite-range couplings"
DTSTART;VALUE=DATE-TIME:20111115T100000Z
DTEND;VALUE=DATE-TIME:20111115T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11297@ictp.it
DESCRIPTION:Parameter estimation is a central issue in system modeling\, t
he tipical setting is to start with a given set of measurements and extrac
t the parameters of a model supposed to describe the system under scrutiny
. The recent availability of large datasets coming from the complex system
has made even more pressing the quest for efficient models\, and the rela
ted parameter extraction techniques. We study Ising chains with arbitrary
multispin finite-range couplings\, providing an explicit solution of the
associated inverse Ising problem\, i.e. the problem of inferring the value
s of the coupling constants from the correlation functions. As an applicat
ion\, we reconstruct the couplings of chain Ising Hamiltonians having expo
nential or power-law two-spin plus three- or four-spin couplings. The gene
ralization of the method to ladders and to Ising systems where a mean-fiel
d interaction is added to general finite-range couplings is also discussed
.\n\n//indico.ictp.it/event/a11297/
LOCATION:SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a11297/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Collective
dynamics of a Bose-Einstein condensate coupled to light"\n\n
DTSTART;VALUE=DATE-TIME:20111117T103000Z
DTEND;VALUE=DATE-TIME:20111117T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11298@ictp.it
DESCRIPTION:Motivated by recent experiments observing self-organization of
Bose--Einstein condensates in optical cavities we investigate the collect
ive dynamics of the associated non-equilibrium Dicke model. We find a rich
phase diagram including distinct superradiant fixed points\, coexistence
phases\, and regimes of persistent oscillations. We explore the intrinsic
timescales for observing these novel phases and discuss the implications f
or finite duration experiments.\n\n//indico.ictp.it/event/a11298/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11298/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "The Casimir effect:
Present status\, theoretical puzzles and \nfuture perspectives"\n
DTSTART;VALUE=DATE-TIME:20111122T103000Z
DTEND;VALUE=DATE-TIME:20111122T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11301@ictp.it
DESCRIPTION:The seminar will provide a pedagogical introduction to the Cas
imir effect.\nAn overview will be given of open theoretical puzzles and of
recent experiments\, with an eye on perpsective applications of the Casi
mir effect to nanotechnology.\n\n//indico.ictp.it/event/a11301/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11301/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Colloquium on Condensed Matter Physics: "Colloida
l monolayers on quasicrystalline surfaces"\n
DTSTART;VALUE=DATE-TIME:20111123T150000Z
DTEND;VALUE=DATE-TIME:20111123T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11305@ictp.it
DESCRIPTION:Monolayers on crystalline surfaces often form complex structur
es having physical and chemical properties strongly differing from those o
f their bulk phases. Such hetero-epitactic overlayers are currently used
in nanotechnology and understanding their growth mechanism is important fo
r the development of novel materials and devices. Compared to crystals\,
quasicrystalline surfaces exhibit much larger structural and chemical comp
lexity leading e.g. to unusual frictional\, catalytical or optical propert
ies. Accordingly\, deposition of thin films onto such substrates can lead
to novel structures which may even exhibit typical quasicrystalline prope
rties. Here we report a real-space investigation of the phase behaviour o
f a colloidal monolayer interacting with a quasicrystalline decagonal subs
trate created by interfering five laser beams. We observe a novel pseudom
orphic phase which exhibits likewise crystalline and quasicrystalline stru
ctural properties and can be described by an Archimedean-like tiling consi
sting of alternating rows of square and triangular tiles. In addition\, w
e also investigate the frictional properties of monolayers on quasiperiodi
c surfaces. Here\, we find that the particles do not follow the applied e
xternal force but that their trajectories exhibit characteristic features
which resemble kink-like excitations also found on periodic surfaces.\n\n/
/indico.ictp.it/event/a11305/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11305/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:"Gate-tuned n
ormal and superconducting transport \nat the surface of a topological insu
lator"\n\n
DTSTART;VALUE=DATE-TIME:20111124T103000Z
DTEND;VALUE=DATE-TIME:20111124T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11304@ictp.it
DESCRIPTION:Three dimensional topological insulators are a novel quantum s
tate of matter which exhibits an insulating bulk state and gapless metalli
c surface. Owing to the large spin-orbit interaction and the ensuing band
structure topology\, these surface states behave as massless\, spin-helica
l Dirac fermions that are protected against backscattering. In this talk I
present recent results of magnetotransport measurements performed on the
3D topological insulator Bi2Se3. The samples studied are nano-connected ul
tra-thin flakes of high quality Bi2Se3 deposited on a SiO2/Si substrate th
at acts as a gate electrode. Such back-gated device allows to vary continu
ously the carrier density by electrostatic doping over the entire Dirac co
ne of the surface state. Under magnetic field B\, sweeping the gate voltag
e enables us to control the filling of the Landau levels\, resulting in Sh
ubnikov-de Haas oscillations of the conductance. The continuous evolution
of the SdH oscillations from electron to hole character gives a clear evid
ence for the Dirac nature of the surface state. After this demonstration o
f the control of electronic transport through the surface states I’ll sh
ow that\, when the electrodes are superconducting at B=0\, Cooper pairs ca
n also be transferred into the surface state leading to a gate-tuned ambip
olar supercurrent.\n\n//indico.ictp.it/event/a11304/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11304/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Optimal protocols a
nd optimal transport in the physics of small systems"\n
DTSTART;VALUE=DATE-TIME:20111129T100000Z
DTEND;VALUE=DATE-TIME:20111129T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11309@ictp.it
DESCRIPTION:Small systems in thermal environments such as particles in opt
ical traps or molecular motors can be driven from one state to another whi
le dissipating work. The statistics of work is related to the free energy
difference between the states by Jarzynski's relation\, but most characte
ristics of the process e.g. the sample variance of Jarzynski's relation\,
or expected released heat or expected work itself depend on protocol detai
ls. We show that in a Langevin equation setting the optimal protocol is e
ssentially given by the backwards-forwards solution of optimal control\, i
nvestigated long ago by F. Guerra and L. Morato in the context of stochas
tic quantization. For the specific case of optimising heat or work the si
tuation simplifies dramatically\, and the coupled backwards-forwards solut
ion reduces to only Burgers equation for an auxiliary field\, and mass tra
nsport by the Burgers velocity field [1].\nI will discuss these results an
d possible extensions and applications. For instance\, if temperature is n
ot constant and time and space an analogous simplification occurs but not
for the heat but instead for the entropy production in the environment. Th
is is joint work with Paolo-Muratore-Ginanneschi\, Carlos Mejia-Monasteiro
\, Stefano Bo\, Antonio Celani and Ralf Eichhorn.\n\n[1] Erik Aurell\, Car
los Mejia-Monasterio\, Paolo Muratore-Ginanneschi\; Optimal protocols and
optimal transport in stochastic thermodynamics\; Phys. Rev. Lett. 106\,
250601 (2011)\n\n//indico.ictp.it/event/a11309/
LOCATION:SISSA\, Santorio Bldg.\, room 128 1st floor
URL://indico.ictp.it/event/a11309/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special interdisciplinry seminar: "Extracting crises information f
rom time series"\n
DTSTART;VALUE=DATE-TIME:20111130T150000Z
DTEND;VALUE=DATE-TIME:20111130T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11306@ictp.it
DESCRIPTION:Using a thermodynamic interpretation of multifractal spectra w
e develop a method to analyze time series. We apply it to data from epile
ptic and healthy patients (electroencephalograms) and show that seizures c
an be clearly distinguished from spurious data. We also apply it to seve
ral examples of financial data showing clearly the appearance of crises.
Since the analysis is based only on previous data\, it is particularly use
ful for predictions.\n\n//indico.ictp.it/event/a11306/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11306/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "The atomic
quasi-periodic kicked rotor: Experimental test of the universality of the
Anderson transition\, critical behaviour and large fluctuations"\n
DTSTART;VALUE=DATE-TIME:20111201T150000Z
DTEND;VALUE=DATE-TIME:20111201T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11308@ictp.it
DESCRIPTION:The quasi-periodic kicked rotor is a one-dimensional system di
splaying the same metal-insulator Anderson transition than a usual 3D diso
rdered system. This model can be experimentally realized using a cold ato
mic gas\, allowing for a direct measurement of the temporal dynamics. Acc
urate measurements of the atomic wavefunction dynamics and the use of fini
te-size scaling techniques make it possible to measure with a good precisi
on the value of the critical exponent \\nu and to test its universality.
We also study the spatio-temporal evolution of the wavefunction at the cr
itical point\, and show that it is well described at short times by self-c
onsistent theory of localization. At long times - probably not accessible
to the present generation of experiments - large deviations are observed\
, related to the multifractal character of the wavefunctions.\n\n//indico.
ictp.it/event/a11308/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11308/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Entanglement entrop
y: Insights from the two intervals case"\n
DTSTART;VALUE=DATE-TIME:20111206T103000Z
DTEND;VALUE=DATE-TIME:20111206T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11310@ictp.it
DESCRIPTION:While the entanglement entropy for one interval in two dimensi
onal CFT is sensible only to the central charge\, in the case of many inte
rvals it includes the full operator content of the theory. We make this st
atement manifest through an OPE expansion valid for any CFT. This general
result is tested quantitatively for the compactified boson and the Ising m
odel\, where the expressions of the Renyi entropies are derived in terms o
f Riemann theta functions. Such expressions are checked against numerical
data obtained from spin chains.\nThe holographic entanglement entropy for
two disjoint intervals in the boundary theory is discussed\, also for the
time dependent backgrounds given by the Vaidya metrics\, which model the b
lack hole formation.\n\n//indico.ictp.it/event/a11310/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11310/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Metal- insu
lator transition in 2D random fermion systems of chiral symmetry classes"\
n\n
DTSTART;VALUE=DATE-TIME:20111208T103000Z
DTEND;VALUE=DATE-TIME:20111208T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11312@ictp.it
DESCRIPTION:We consider localization of Dirac fermions in graphene with st
rong scatterers and\, more generally\, metal-insulator transition in 2D di
sordered systems with chiral symmetry. A general approach is developed to
describe a disordered sample with strong isolated scatterers. This approac
h provides a basis for an efficient numerical analysis of the charge trans
port and is applied to calculate the conductivity of undoped graphene with
resonant impurities. In the case of smooth resonant scatterers\, the symm
etry class is identified as DIII and conductivity grows logarithmically wi
th increasing impurity concentration. For vacancies (or strong on-site pot
ential impurities\, class BDI)\, conductivity saturates at a constant valu
e that depends on the vacancy distribution among six sublattices. A genera
l analysis of the metal-insulator transition in 2D system of a chiral symm
etry class (AIII\, BDI\, and DIII) is based on the replica sigma-model for
malism. Weak localization corrections to conductivity are absent in all or
ders of perturbation theory. We identify the non-perturbative contribution
s due to topological excitations. These excitations have the form of vorti
ces\; their dynamics leads to the metal-inculator transition analogous to
the Berezinskii-Kosterlitz-Thouless transition in the 2D Coulomb gas. This
vortex-driven mechanism becomes ineffective when the system possesses non
-trivial topological properties (Wess-Zumino term in class AIII or Z_2 top
ological term in class CII). This\, in particular\, explains the lack of l
ocalization on the surface of a 3D topological insulator of class CII.\n\n
//indico.ictp.it/event/a11312/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11312/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Exciton hierarchies
in carbon nanotubes"\n
DTSTART;VALUE=DATE-TIME:20111213T100000Z
DTEND;VALUE=DATE-TIME:20111213T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11323@ictp.it
DESCRIPTION:I present evidence that the strong electron-electron interacti
ons in gapped carbon nanotubes lead to finite hierarchies of excitons wi
thin a given nanotube subband. I study these hierarchies by employing a
field theoretic reduction of the gapped carbon nanotube permitting ele
ctron-electron interactions to be treated exactly. I analyze this reduct
ion by employing a Wilsonian-like numerical renormalization group. I am
so able to determine the gap ratios of the one-photon excitons as a func
tion of the effective strength of interactions. I also determine within
the same subband the gaps of the two-photon excitons\, the single partic
le gaps\, as well as a subset of the dark excitons. The strong electron-
electron interactions in addition lead to strongly renormalized dispersi
on relations where the consequences of spin-charge separation can be rea
dily observed.\n\n//indico.ictp.it/event/a11323/
LOCATION:SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a11323/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar: "Nanostructures on metallic surfaces: Novel magn
etic properties"\n\n
DTSTART;VALUE=DATE-TIME:20111214T150000Z
DTEND;VALUE=DATE-TIME:20111214T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11324@ictp.it
DESCRIPTION:The magnetic properties of nanostructures supported on metalli
c surfaces are of great interest\, both because of the possibilities of at
omic engineering of future spintronic devices\, as well as due to the fact
that such systems challenge our understanding of magnetism in general. He
re\, our research on the magnetic properties of nano-sized objects adsorbe
d on different substrates will be reviewed. Such theoretical investigation
s were performed using DFT (Density Functional Theory) based method\, whic
h is appropriate to treat complex magnetic structures [1]. From nanowires
to corrals\, we have explored the possibility of the occurrence of novel m
agnetic behaviors. A systematic study of the occurrence of noncollinear ma
gnetism is presented\, by changing the geometry of the supported nanostruc
tures\, where intriguing noncollinear magnetic ordering were obtained for
Mn nanostructures adsorbed on Pt(111) [2]\, Fe(001) and W(001) surfaces. I
n particular\, for Mn corrals on Pt(111) surfaces we identified a nano¬ob
ject presenting very complex stable magnetic configurations\, which can be
described by topological structures\, as Skyrmions\, in analogy to Z2 vor
tex¬like structures [2]. Also\, for Mn nanostructures on Fe(001) the effe
ct of spin-orbit coupling lead to the possibility of half skyrmion. Concer
ning metallic nanowires of Mn on W(001)\, we show the possibility of reali
zing complex noncollinear magnetic structures such as helical spin spiral.
\n[1] A. Bergman\, L. Nordström\, A. B. Klautau\, S. Frota¬Pessôa and
O. Eriksson\, Phys. Rev. B 73\, 174434 (2006)\; Phys. Rev. B 75\, 224425 (
2007). \n[2] M. S. Ribeiro\, G. B. Corrêa Jr.\, A. Bergman\, L. Nordströ
m\, O. Eriksson\, and A. B. Klautau\, Phys. Rev. B 83\, 014406 (2011).\n\n
//indico.ictp.it/event/a11324/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11324/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: \n" Theory a
nd experiments with quantum fluids of light: from superfluid hydrodynamics
to quantum Hall liquids "
DTSTART;VALUE=DATE-TIME:20111215T103000Z
DTEND;VALUE=DATE-TIME:20111215T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a11325@ictp.it
DESCRIPTION:A few years after the first observation of Bose-Einstein conde
nsation in quantum gases of exciton-polaritons in semiconductor microcavi
ties\, these systems turn out to be very promising candidates for the stu
dy of many-body effects in a novel non-equilibrium context. In this talk
\, I shall first present the recent experiments that have recently demons
trated superfluid hydrodynamics effects in polariton gases and I shall tr
y to address a few conceptual questions on the meaning of superfluidity a
nd Bose-Einstein condensation for non-equilibrium systems. In the second
part\, I will review a few most significant theoretical advances towards
the generation of strongly correlated states of photons\, from Tonks-Girar
deau gases of impenetrable photons in 1D\, to quantum Hall liquids in the
presence of artificial magnetic fields.\n\n//indico.ictp.it/event/a11325/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a11325/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:\n"Three stud
ies of correlated electrons on honeycomb lattice"\n
DTSTART;VALUE=DATE-TIME:20120119T103000Z
DTEND;VALUE=DATE-TIME:20120119T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a125@ictp.it
DESCRIPTION:The effect of electron correlation on honeycomb lattice has at
tracted a lot of interest recently. In this talk\, I will present the resu
lts of three analytical studies of correlated electrons on honeycomb latti
ce. In the first study\, we provide an analytical argument for the absence
of topological degeneracy in the "Mott insulating" state found recently
in the Hubbard model on honeycomb lattice. In the second study\, we propos
e a SU(2) generalization of staggered flux phase on honeycomb lattice\, wh
ich reveals the close relation between the RVB physics on square lattice a
nd honeycomb lattice. In the third study\, we predict that the quarter-dop
ed Hubbard model on honeycomb lattice will realize a magnetic ordered grou
nd state with non-zero spin chirality and quantized Hall conductivity. It
is argued that such an exotic state should be observable in quarter-doped
graphene system.\n\n//indico.ictp.it/event/a125/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a125/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar:\n" Fractional Langev
in Equation and its application to linear stochastic models "
DTSTART;VALUE=DATE-TIME:20120124T103000Z
DTEND;VALUE=DATE-TIME:20120124T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a129@ictp.it
DESCRIPTION:The Generalized Elastic Model accounts for the dynamics of sev
eral physical systems\, such as polymers\, fluctuating interfaces\, growin
g surfaces\, membranes\, proteins and file systems among others. We derive
the fractional stochastic equation governing the motion of a probe pa
rticle (tracer) in such kind of systems. This Langevin equation involves
the use of fractional derivative in time and satisfies the Fluctuation-Dis
sipation relation\, it goes under the name of Fractional Langevin Equation
. Within this framework the spatial correlations appearing in the General
ized Elastic Model are translated into time correlations described by the
fractional derivative together with the space-time correlations of the fr
actional Gaussian noise. We derive the exact scaling analytical form of se
veral physical observables such as structure factors\, roughness and mean
square displacement. Special attention will be devoted to the dependence o
n initial conditions and linear-response relations in the case of an appli
ed potential.\n\n//indico.ictp.it/event/a129/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a129/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Colloquium on Condensed Matter Physics:\n"Interpr
etation and prediction of nanostructural evolution based on first-principl
es studies"
DTSTART;VALUE=DATE-TIME:20120125T153000Z
DTEND;VALUE=DATE-TIME:20120125T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a124@ictp.it
DESCRIPTION:Pattern formation and decay in the early stage of growth is fu
ndamental to many materials physics and chemistry. Understanding the compl
ex interplay between factors that influence the evolution of surface-based
nanostructures can be challenging. Computer simulation will play an impo
rtant role in providing insight. In this talk\, I will first introduce a o
ne-\, two-\, and three-dimensional Ehrlich-Schwoebel (ES) barrier in kinet
ics-driven growth. Within this framework\, I will show how to control the
island shape\, the island instability\, and the film roughness efficiently
. Furthermore\, I will discuss a novel concept: a true upward adatom diffu
sion on metal surface\, which is beyond the traditional Ehrlich-Schwoebel
(ES) barrier model. This process offers new indications as how to use ab i
nitio kinetic Monte Carlo simulation can uncover some of the building regu
lations of the evolution mechanism down to atomic-scale.\n\n//indico.ictp.
it/event/a124/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a124/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:\n" Quantum F
luctuations and Dynamic Clustering of Fluctuating Cooper Pairs "
DTSTART;VALUE=DATE-TIME:20120126T103000Z
DTEND;VALUE=DATE-TIME:20120126T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1210@ictp.it
DESCRIPTION:We derive the exact expressions for the fluctuation conductivi
ty in two dimensional superconductors as a function of temperature and mag
netic field in the whole phase diagram above the upper critical field line
Hc2(T). Focusing on the vicinity of the quantum phase transition near zer
o temperature we arrive to the conclusion that as the magnetic field appro
aches the critical field Hc2(0) from above\, a peculiar dynamic state cons
isting of clusters of coherently rotating fluctuation Cooper-pairs forms.
We estimate the characteristic size QF( H) and lifetime QF( H) of such
clusters and indicate in the corresponding domain of the phase diagram\, w
here such phenomenon can be observed. The derived values QF( H) and QF(
H) allow us to reproduce qualitatively the available results for the quan
tum fluctuation contributions to the in-plane conductivity\, magnetization
\, and the Nernst coefficient. Finally we predict the existence of a peak
in the zero temperature transverse magneto-conductivity of layered superco
nductors at fields above Hc2(0).\n\n//indico.ictp.it/event/a1210/
LOCATION:ICTP
URL://indico.ictp.it/event/a1210/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: " Higher level Integ
rals of Motion from ODEs in the complex plane "
DTSTART;VALUE=DATE-TIME:20120131T103000Z
DTEND;VALUE=DATE-TIME:20120131T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1214@ictp.it
DESCRIPTION:In this talk I will revise the basic ideas underlying a powerf
ul correspondence between integrable models and ordinary differential equa
tions (or IM/ODE correspondence\, for short). This spectral equivalence pl
ayed an important role in the study of PT-symmetry\, providing rigorous pr
oofs about the spectra of an important class of non-Hermitian Hamiltonians
based on known integrable results. My intention is to make progress in th
e opposite direction\, namely to extract information about integrable syst
ems by using differential equations. The comparison between the eigenvalue
s of the ODEs and the spectral parameters in certain Quantum Integrable Mo
dels is considerably well understood for the vacuum state of the latter. F
or excited states\, however\, results are only known for the problem with
su(2) symmetry. Here I will show this can be extended to the su(2|1) super
-symmetric problem in order to establish the exact correspondence also for
excited states.\n\n//indico.ictp.it/event/a1214/
LOCATION:SISSA\, Santorio Bldg\, Room 128
URL://indico.ictp.it/event/a1214/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: \n" Competin
g spin-disordered phases of the spin-1/2 Heisenberg antiferromagnet on the
Kagome lattice "
DTSTART;VALUE=DATE-TIME:20120202T103000Z
DTEND;VALUE=DATE-TIME:20120202T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1215@ictp.it
DESCRIPTION:Despite years of intense theoretical attack from different dir
ections\, the ground state of the S = 1/2 Kagome Heisenberg antiferromagne
t has remained elusive. I will revisit this question within the framework
of Gutzwiller projected fermionic wave functions studied using Variational
quantum Monte Carlo technique. We found the so called U(1) Dirac state\,
an exotic algebraic spin liquid\, to have the best variational energy. Whi
le there were doubts concerning its stability\, experiments have hinted to
wards a gapless\, algebraic spin liquid behavior. Indeed we show that the
U(1) Dirac spin liquid is remarkably stable w.r.t dimerizing towards a lar
ge class of Valence bond crystal perturbations.\n\nThis stability is also
preserved upon addition of a weak 2nd NN exchange couplings. However we fi
nd\, that upon addition of a weak 2nd NN ferromagnetic coupling\, a non-tr
ivial valence bond crystal is stabilized\, and has the lowest energy. This
VBC possesses a non-trivial flux pattern and is a strong dimerization of
another competing U(1) gapless spin liquid with a large spinon Fermi surfa
ce\, the so called uniform RVB state. The U(1) Dirac state and the uniform
RVB state are shown to be remarkably stable w.r.t. destabilizing into the
class of Z2 spin liquids.\n\nI will also briefly touch upon my ongoing wo
rk dealing with a complete group theoretical classification of time-revers
al invariant Valence bond crystals on the Kagome lattice\, and present som
e results concerning the properties of the ground state on small clusters
which are extracted using the Lanczos method on a given variational wave f
unction.\n\n//indico.ictp.it/event/a1215/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1215/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special Seminar in Statistical Physics: " On the exponents of the
critical slowing down in Mode Coupling Theory "
DTSTART;VALUE=DATE-TIME:20120203T103000Z
DTEND;VALUE=DATE-TIME:20120203T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1219@ictp.it
DESCRIPTION:An important prediction of Mode-Coupling-Theory (MCT) is the r
elationship between the decay exponents in the beta regime: Gamma2(1-a)/G
amma(1-2a) = Gamma2(1+b)/Gamma(1+2b)= lambda. In the original structural
glass context this relationship follows from the MCT equations that are ob
tained making rather uncontrolled approximations. As a consequence\, it is
usually assumed that the relationship between the exponents is correct wh
ile lambda has to be treated like a tunable parameter. On the other hand\,
it is known that in some mean-field spin-glass models the dynamics is pre
cisely described by MCT. When we are in the so called "schematic" case\,
lambda can be computed exactly but\, again\, its computation becomes diffi
cult when we consider more complex models including finite-dimensional one
s. We have been able to unveil the physical meaning of lambda in complete
generality\, relating the dynamical parameter to the static Gibbs free ene
rgy and giving\, thus\, a ``recipe'' for its computation. In this new fram
ework we compute the exponents a and b for some mean-field models and comp
are our results with numerical simulations or\, when available\, exact res
ults obtained via purely dynamical equations.\n\n//indico.ictp.it/event/a1
219/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1219/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special Seminar in Statistical Physics: " Ensemble Renormalization
Group for Disordered Systems "\n
DTSTART;VALUE=DATE-TIME:20120207T103000Z
DTEND;VALUE=DATE-TIME:20120207T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1225@ictp.it
DESCRIPTION:We study a Renormalization Group transformation that can be us
ed also for models with quenched disorder\, like spin glasses. The method
is based on a mapping between disorder distributions\, chosen such as to k
eep some physical properties (e.g. the ratio of correlations) invariant un
der the transformation. We validate this Ensemble Renormalization Group by
applying it to the hierarchical model (both the diluted ferromagnetic ver
sion and the spin glass version)\, finding results in agreement with Monte
Carlo simulations.\n\n//indico.ictp.it/event/a1225/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1225/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special Seminar in Condensed Matter Physics: "Ab-initio electronic
structure calculations of Transparent Conducting Oxide (TCO) materials "
DTSTART;VALUE=DATE-TIME:20120208T153000Z
DTEND;VALUE=DATE-TIME:20120208T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1226@ictp.it
DESCRIPTION:Transparent Conducting Oxides (TCO) constitute an unique class
of materials which combine two physical properties - transparency for vis
ible spectrum and high electrical conductivity together. TCO's are widely
used in a variety of technological applications and are subject of active
experimental and theoretical research. Development of an electronic struct
ure method capable of accurately describing the key physical properties of
TCO namely - the band gap and electron effective mass has been a subject
of enduring interest. \nIn this talk\, I will first discuss the electronic
band structure of basic TCO's calculated using density functional theory
(DFT). It is observed that although the structural parameters are correct\
, the DFT band gap are severely underestimated compared to experiment. Sin
ce DFT is a ground state theory and in principle the Kohn-Sham gaps can no
t be compared with the experiment\, we use the state of the art - GW appro
ximation technique to calculate the excited states. The implementation of
the GW approximation within ABINIT code will be presented in brief. The mo
difications in the pseudopotential necessary for accurate calculation of t
he self-energy within the GW approximation is discussed with the help of a
systematic study of the pseudopotentials for ZnO. The GW results are pres
ented for ZnO\, SnO_2 and ZnX_2O_4 (X=Al\, Ga and In) spinel structure. Fi
nally I will also discuss the electronic band structure calculated using t
he computationally inexpensive Tran-Blaha modified Becke-Johnson potential
(TB-mBJ) scheme for prototype TCO's and formation energies of native poin
t defects in ZnAl_2O_4 spinel structure.\n\n//indico.ictp.it/event/a1226/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1226/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on disorder and strong correlations: "Statistical mechanic
s of harmonic spheres: Glass and jamming transition"
DTSTART;VALUE=DATE-TIME:20120209T103000Z
DTEND;VALUE=DATE-TIME:20120209T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1235@ictp.it
DESCRIPTION:When a fluid is cooled down sufficiently rapidly to avoid crys
tallization\, its dynamics slow down very rapidly\, and an amorphous solid
is formed. This phenomenon is called the glass transition.\nWhen piling
randomly in a box more and more spheres\, a density is eventually attained
\, where all spheres come in contact. At this density and upon further co
mpression\, the system acquires rigidity: it is the jamming transition.\nJ
amming and glass transition are very old statistical mechanics problems th
at are often associated with one another\, because intuition suggests that
both phenomenons arise from the same physical effect\, the caging of each
particle by its shell of neighbours.\nDuring my phd thesis\, I studied an
alytically a model system of harmonic spheres (soft spheres that repel eac
h other with finite amplitude and finite range)\, that allows to simultane
ously study the jamming and the glass transition.\nI will present results
obtained on the dynamics near the glass transition\, as well as thermodyna
mics near the jamming point\, with field theoretic methods and replica the
ory.\n\n//indico.ictp.it/event/a1235/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1235/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar: "Quantum current noise in a superconducting singl
e electron transistor"
DTSTART;VALUE=DATE-TIME:20120210T103000Z
DTEND;VALUE=DATE-TIME:20120210T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1229@ictp.it
DESCRIPTION:We present a method for calculating the asymmetric quantum cur
rent noise in systems described by a Born-Markov master equation. The tec
hnique is particularly suited to describing mesoscopic devices containing
Josephson junctions. As an example we calculate the full frequency depen
dent current noise in a superconducting single electron transistor tuned t
o the double Josephson quasiparticle resonance. Our results are consisten
t with those obtained in a recent experiment which was able to probe the a
symmetric noise.\n\n//indico.ictp.it/event/a1229/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1229/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar: "Energy landscape of fullerene materials: A comp
arison of boron to boron nitride and carbon"\n
DTSTART;VALUE=DATE-TIME:20120213T093000Z
DTEND;VALUE=DATE-TIME:20120213T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1228@ictp.it
DESCRIPTION:After the discovery of the C60 fullerene some 25 years ago\, m
any more hollow and endohedrally doped structures made out of various elem
entshave been proposed theoretically. However\, since no other fullerenes
have been synthesized up to date \, the question arises whether experiment
alists have just not yet found a way to synthesize these theoretically pre
dicted fullerenes\, or whether they do not exist at all in nature.\nFollow
ing the theoretical discovery of the B_80 fullerene by Szwacki et al\, va
rious other fullerene and stuffed fullerene structures were proposed but n
one of them could be synthesized in the laboratory yet. Using the minima
hopping global geometry optimization method on the density functional po
tential energy surface we show that the energy landscape of boron cluster
s is glass like.\nMedium size boron clusters exhibit many structures which
are lower in energy than the cages. This is in contrast to carbon and bo
ron nitride systems which can be clearly identified as structure seekers.
The differences in the potential energy landscape explain why carbon and
boron nitride systems are found in nature whereas pure boron fullerenes h
ave not been found. We thus present a methodology which can make predictio
ns on the feasibility of the synthesis of new nano structures.\n\n//indico
.ictp.it/event/a1228/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1228/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Colloquium on Condensed Matter Physics: " Photons
\, dust and honey bees "
DTSTART;VALUE=DATE-TIME:20120215T153000Z
DTEND;VALUE=DATE-TIME:20120215T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1242@ictp.it
DESCRIPTION:Lévy flights determine how animals search for food\, how eart
hquakes are distributed\, and how the stock market goes up and down daily.
\nIn this talk\, I will explain how one can realize optical materials i
n which light waves follow Lévy flights\, and which new possibilities thi
s offers in photonics. \nDisordered photonic materials have surprisingly i
nteresting physical properties\, and allow to study the fundamental physic
s of transport processes. On the other hand\, their fascinating optical re
sponse leads to unexpected effects\, like the efficient trapping of light
in thin films. The latter property turns out to be very valuable for impro
ving thin film photo-voltaic solar cells and creating new light sources.\n
\n//indico.ictp.it/event/a1242/
LOCATION:SISSA\, Santorio Bldg.\, Room 128 1st floor
URL://indico.ictp.it/event/a1242/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar: "Transport properties of thin superconducting fil
ms"
DTSTART;VALUE=DATE-TIME:20120220T100000Z
DTEND;VALUE=DATE-TIME:20120220T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1244@ictp.it
DESCRIPTION:Transport properties of 2D superconducting systems can be very
different from those of bulk superconductors because thermal and quantum
fluctuations of superconducting order parameter are more pronounced and p
lay a crucial role. First we focus on the influence of superconducting fl
uctuations on dynamics\, while the system is in the normal state but clos
e to the superconducting transition. In the fluctuational regime\, we der
ive a Ginzburg-Landau-type action under far-from equilibrium conditions.
Then\, utilizing it\, we calculate the fluctuation-induced density of sta
tes and Maki-Thomson- and Aslamazov-Larkin-type contributions to the in-pl
ane electrical conductivity [1\,2]. We propose an experimental setup wher
e our results can be tested: thin superconducting film sandwiched between
a gate and a substrate\, which have different temperatures and different
electrochemical potentials.\nThen\, we concentrate on transport at lower t
emperatures in close-to-equilibrium conditions investigating influence of
quantum fluctuations on the unbinding of vortex-antivortex pairs. We dete
rmine the temperature below which quantum fluctuations dominate over therm
al fluctuations and describe the transport in this quantum regime. The
crossover from the quantum to the classical regime is discussed and the qu
antum correction to the classical current-voltage relation is determined [
3].\n\n[1] Phys. Rev. Lett. 105\, 187003 (2010)\n[2] Phys. Rev. B 84\, 064
510 (2011)\n[3] Phys. Rev. B 80\, 212504 (2009)\n\n//indico.ictp.it/event
/a1244/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1244/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "A statistical mecha
nics perspective on immune networks"\n
DTSTART;VALUE=DATE-TIME:20120221T103000Z
DTEND;VALUE=DATE-TIME:20120221T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1246@ictp.it
DESCRIPTION:We present some recent investigations on systemic features of
the immune system\, based on a statistical mechanics approach. We first i
ntroduce a mean-field spin-glass model for the interaction between helper
cells and the effector branches (B and K cells) able to reproduce\, as eme
rging properties\, several collective phenomena shown in real immune netwo
rks (e.g. the connection between autoimmunity and lymphoproliferative diso
rders or the breakdown of immunosurveillance by lymphocyte unbalance). We
also show that this system can be mapped into an associative neural netwo
rk\, where helper cells directly interact with each other and are able to
orchestrate an immune response retrieving "strategies'' previously learnt.
Then\, we go beyond the fully-connected approximation by introducing dilu
tion in the interactions between helpers and effectors and show that this
makes the former able to retrieve parallel strategies to fight several pat
hogens simultaneously. That is to say\, dilution\, which is a biological r
equisite\, results in multitasking capabilities.\n\n//indico.ictp.it/event
/a1246/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1246/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on on Disorder and strong electron correlations:\n"Localiz
ation of hybrid particles"
DTSTART;VALUE=DATE-TIME:20120223T103000Z
DTEND;VALUE=DATE-TIME:20120223T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1247@ictp.it
DESCRIPTION:Motivated by various disordered propagation problems with comp
eting channels\, I study the representative problem of Anderson localizati
on on an asymmetric two-leg ladder. The problem is solved by the Fokker-P
lanck approach\, which is exact in the weak disorder limit. The localizat
ion radius of various one dimensional systems\, such as a polaritons or ot
her hybrid particles\, can be investigated by this model. These applicati
ons correspond to parametrically different intra-chain hopping integrals a
nd/or different disorder amplitudes on the two legs\, situations in which
it is non-trivial to predict what dominates the transport in the joint sys
tem.\nAn extended Dorokhov-Mello-Pereya-Kumar (DMPK) equation is obtained
and solved analytically. Two localization lengths are obtained as functio
ns of the parameters of the model. We find that: 1) Near the resonance en
ergy (where the dispersion curves of the two decoupled and disorder-free\
nchains intersect) the "slow'' chain dominates the localization properti
es of the ladder. 2) Away from the resonance the "fast'' chain dominates
the transmission probability.\n\n//indico.ictp.it/event/a1247/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1247/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Zamolodchikov-Fadde
ev algebra and quantum quenches in integrable field theories"\n
DTSTART;VALUE=DATE-TIME:20120228T100000Z
DTEND;VALUE=DATE-TIME:20120228T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1248@ictp.it
DESCRIPTION:Motivated by the study of quantum quenches in integrable field
theories (IFTs) and in particular the structure of the initial state afte
r such a quench\, we are led to the investigation of transformations of th
e Zamolodchikov-Faddeev operators that respect their algebra. After showin
g that\, unlike in free theories\, linear transformations (Bogoliubov tran
sformations) do not satisfy this condition\, we explore simple cases of in
finitesimal transformations that do so and study their properties. Example
s from typical IFTs like the Sinh-Gordon and Lieb-Liniger models are prese
nted\, emphasizing the possibility to study quantum quenches.\n\n//indico.
ictp.it/event/a1248/
LOCATION:SISSA\, Santorio Bldg.\, room 128 1st floor
URL://indico.ictp.it/event/a1248/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on disorder and strong electron correlations: "Geometric c
rossover between the Kondo effect and the 0.7-anomaly: A Fermi-liquid pers
pective"
DTSTART;VALUE=DATE-TIME:20120301T103000Z
DTEND;VALUE=DATE-TIME:20120301T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1261@ictp.it
DESCRIPTION:Quantum point contacts and quantum dots\, two elementary build
ing blocks of semiconducting nanodevices\, both exhibit famously anomalous
conductance features at low energy scales: the 0.7-anomaly in the former
case\, the Kondo effect in the latter. For both effects the conductance sh
ows a remarkably similar low-energy dependence on temperature (T)\, magnet
ic field (B) and source-drain voltage. This has led to the suggestion tha
t the 0.7-anomaly and the Kondo effect have the same microscopic origin.
Here we explore this notion theoretically and experimentally by studying t
he geometric crossover between a quantum dot and a quantum point contact.
We introduce a one-dimensional model that reproduces the essential featur
es of the geometry- and B-dependence of the conductance at T=0 for both Ko
ndo effect and 0.7-anomaly. Though their properties differ markedly at hi
gh energies\, at low energies there are striking similarities. We attribu
te the latter to similar interaction-enhanced spin-fluctuations in regions
of low charge density and conjecture that these can be described using si
milar Fermi-liquid theories. Our predictions are consistent with our expe
rimental results\, which confirm\, in particular\, that the 0.7-anomaly e
xhibits Fermi-liquid behavior at low B and T. We also explain in detail h
ow the 0.7-structure at T=B=0 arises from a combination of geometry and in
teraction effects.\n\n//indico.ictp.it/event/a1261/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1261/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Arrhenius law out o
f equilibrium"
DTSTART;VALUE=DATE-TIME:20120306T103000Z
DTEND;VALUE=DATE-TIME:20120306T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1263@ictp.it
DESCRIPTION:The Arrhenius law appears in many different physical contexts.
It is one of the most important laws governing the behavior of systems c
haracterized by energy scales which are much smaller than the temperature.
We shall derive and discuss its extension out of equilibrium. We will fo
cus on classical systems which are out of equilibrium either because they
are subjected to non-potential forces or because they are coupled to an ou
t of equilibrium thermal bath. A generalization of time-reversal\, that
already emerged in the context of fluctuation theorems out of equilibrium\
, plays a key role in our derivation and will be discussed thoroughly. We
shall conclude by discussing applications and further extensions of our re
sults.\n\nWork in collaboration with Serena Bradde.\n\n//indico.ictp.it/ev
ent/a1263/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1263/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter seminar: " Ions in water: The am
orphous silica interface and the recombination of H30+ and OH- "
DTSTART;VALUE=DATE-TIME:20120307T150000Z
DTEND;VALUE=DATE-TIME:20120307T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1266@ictp.it
DESCRIPTION:In this talk I will begin by sharing results on the structure
and dynamics of ions at the water-amorphous silica interface. For 80 years
\, scientists have employed models in which ions and water near the silica
surface form a stagnant layer called the Stern layer. To account for all
experimental features\, these models invoke puzzling properties such as t
he transport of ions through immobile water. In this talk I will present
a realistic theoretical description of the water-amorphous silica interfac
e. We have successfully constructed and validated a model for the water-am
orphous silica interface and have begun to examine the fate of biomolecule
s near this important interface. Our simulations challenge the classical t
extbook Stern layer model. Both ions and water exhibit a substantial degr
ee of mobility\, yet the phenomena the Stern layer was originally invoked
to explain\, are reproduced by our calculations.\nIn the second part of my
talk I will discuss some very recent results on the mechanism of the reco
mbination of hydronium and hydroxide ions in water. This process following
water ionization is one of the most fundamental processes determining the
pH of water. The neutralization step once the solvated ions are in close
proximity\, is phenomenologically understood to be fast but the molecular
mechanism has not been directly probed by experiments. We elucidate the
mechanism of recombination in liquid water with ab initio molecular dynami
cs simulations and it emerges as quite different from the conventional vie
w of the Grotthuss mechanism. The neutralization event involves a collecti
ve compression of the water wire bridging the ions which occurs in 0.5 ps
triggering a concerted triple-jump of the protons. This process leaves the
neutralized hydroxide in a hypercoordinated state\, with the implications
that enhanced collective compressions of several water molecules around s
imilarly hypercoordinated states\, are likely to serve as nucleation event
s for the autoionization of liquid water.\n\n//indico.ictp.it/event/a1266/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1266/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Engineering
Dirac points with ultracold fermions in optical lattices"\n\n
DTSTART;VALUE=DATE-TIME:20120308T103000Z
DTEND;VALUE=DATE-TIME:20120308T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1265@ictp.it
DESCRIPTION:Dirac points lie at the heart of many fascinating phenomena in
condensed matter physics\, from massless electrons in graphene to the eme
rgence of conducting edge states in topological insulators. At a Dirac po
int\, two energy bands intersect linearly and the particles behave as rela
tivistic Dirac fermions. In solids\, the rigid structure of the material
sets the mass and velocity of the particles\, as well as their interaction
s. A different\, highly flexible approach is to create model systems usin
g fermionic atoms trapped in an optical lattice\, a method which so far ha
s only been applied to explore simple lattice structures. In my talk I wi
ll report on the creation of Dirac points with adjustable properties in a
tunable honeycomb optical lattice. Using momentum-resolved interband tran
sitions\, we observe a minimum band gap inside the Brillouin zone at the p
osition of the Dirac points. We exploit the unique tunability of our latt
ice potential to adjust the effective mass of the Dirac fermions by breaki
ng the inversion symmetry of the lattice. Moreover\, changing the lattice
anisotropy allows us to move the position of the Dirac points inside the
Brillouin zone. When increasing the anisotropy beyond a critical limit\,
the two Dirac points merge and annihilate each other. We map out this top
ological transition in lattice parameter space and find excellent agreemen
t with ab initio calculations. Our results not only pave the way to model
materials where the topology of the band structure plays a crucial role\,
but also provide the possibility to explore many-body phases resulting fr
om the interplay of complex lattice geometries with interactions.\n\n//ind
ico.ictp.it/event/a1265/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1265/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Entanglement in fre
e-particle models"
DTSTART;VALUE=DATE-TIME:20120313T100000Z
DTEND;VALUE=DATE-TIME:20120313T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1275@ictp.it
DESCRIPTION:Free many-particle systems have relatively simple eigenstates.
Nevertheless\, these states possess non-trivial entanglement properties
which serve as points of orientation for the whole field. In the talk\, i
t will be shown how one can obtain them from the correlations in the state
\, how this leads to a statistical physics problem and what the nature of
this problem is. The resulting spectra\, which contain the basic entangle
ment information\, will be discussed for a number of cases and an outline
of further topics will be given.\n\n//indico.ictp.it/event/a1275/
LOCATION:SISSA\, Santorio Bldg.\, Room 128
URL://indico.ictp.it/event/a1275/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Coulomb dra
g in graphene"
DTSTART;VALUE=DATE-TIME:20120315T103000Z
DTEND;VALUE=DATE-TIME:20120315T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1270@ictp.it
DESCRIPTION:We study the effect of Coulomb drag between two closely positi
oned graphene monolayers. In the limit of weak electron-electron interact
ion and small inter-layer spacing the drag is described by a universal fun
ction of the chemical potentials of the layers measured in the units of te
mperature. When both layers are tuned close to the Dirac point (i.e. when
both chemical potentials are much smaller than temperature)\, then the dr
ag coefficient is proportional to the product of the chemical potentials.
In the opposite limit of low temperature the drag is inversely proportion
al to the product of the chemical potentials. In the mixed case where the
chemical potentials of the two layers belong to the opposite limits we fi
nd that the drag coefficient is proportional to the smaller chemical poten
tial and inverse proportional to the larger. For stronger interaction and
larger values of the inter-layer spacing the drag coefficient acquires lo
garithmic corrections and can no longer be described by a power law. Furt
her logarithmic corrections are due to the energy dependence of the impuri
ty scattering time in graphene (if both chemical potentials are much large
r than temperature\, then these are small and may be neglected). In the c
ase of strongly doped (or gated) graphene (i.e. when the chemical potentia
l are much larger than the inverse inter-layer spacing) the drag coefficie
nt acquires additional dependence on the inter-layer spacing and we recove
r the usual Fermi-liquid result if the screening length is smaller than th
e spacing.\n\n//indico.ictp.it/event/a1270/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1270/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Some results on the stri
pe-glass phase in 2-d and on ergodicity properties\nof the Anderson model"
DTSTART;VALUE=DATE-TIME:20120319T101500Z
DTEND;VALUE=DATE-TIME:20120319T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1281@ictp.it
DESCRIPTION:I will present results on two of my topics of interest. In the
first part\nwe investigate the existence of a stripe-glass phase in a two
-dimensional\nsystem with no quenched disorder\, which is however frustrat
ed by the\ncompetition of interactions on different length scales. The con
figurational\nentropy is computed through a method applied to frustrated s
ystems with no\nquenched disorder\, and through a 1/N expansion of the gla
ss free energy.\nThe stripe-glass phase is connected to the appearance of
a finite\noff-diagonal replica correlation function\, below a crossover te
mperature\,\nrelated to the mobility of defects in the sample. The off-dia
gonal\ncorrelations in replica space are connected to the asymptotic limit
of the\ntwo-times dynamic correlation function. Within this approach we f
ind no\nfinite contribution for the correlation between distinct replicas\
, which\nresults in a vanishing configurational entropy. Therefore\, we co
nclude that\nglassiness does not emerge at any temperature in the aforemen
tioned model.\n\nIn the second part I will present some results on the erg
odicity properties\nof the Anderson model defined on the Bethe lattice. Ou
r study is motivated\nby the conjectured existence of a phase for intermed
iary disorder strength\nvalues whose ergodicity properties are distinct fr
om the fully ergodic\nextended phase\, as well as from the completely ergo
dicity broken localised\none. This kind of phase is seen to occur on other
models such as the\nDirected Polymer with random complex weights. For an
ensemble of system's\nrealizations\, we have studied eigenvalues and eigen
states statistics\nthrough exact diagonalization. In particular we analyse
d the neighboring\ngaps ratio statistics\, the statistics of inverse parti
cipation ratios\,\nincluding multifractality analysis. We find evidence of
the presence of an\nintermediary disorder phase whose corresponding stati
stics are neither\nexpressing extended nor localised states.\n\n//indico.i
ctp.it/event/a1281/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1281/
END:VEVENT
BEGIN:VEVENT
SUMMARY:ICTP/SISSA Statistical physics seminar: "Quenching the Lieb-Linige
r model"
DTSTART;VALUE=DATE-TIME:20120320T103000Z
DTEND;VALUE=DATE-TIME:20120320T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1279@ictp.it
DESCRIPTION:Quantum quenches for the 1D Bose gas (Lieb-Liniger model) are
discussed.\nThe first part of the talk discusses how the Algebraic Bethe A
nsatz can be used for quantum quenches. As an explicit example we quench
the Lieb-Liniger model by instantaneously switching off the interactions.
The subsequent time evolution is studied for various correlation function
s. The long time average is compared with the predictions of several stat
istical ensembles.\nThe second part concerns the discussion of the general
ized Gibbs ensemble for the Lieb-Liniger model by generalizing the well kn
own TBA equations.\nPossible applications and strategies are discussed.\n\
n//indico.ictp.it/event/a1279/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1279/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar: "Full counting statistics of the \ninteracting re
sonant level model"\n
DTSTART;VALUE=DATE-TIME:20120321T150000Z
DTEND;VALUE=DATE-TIME:20120321T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1280@ictp.it
DESCRIPTION:We discuss the full counting statistics of charge transport th
rough a nano device and introduce a general way to calculate it numericall
y at zero-temperature. We apply this to a strongly correlated model: the
interacting resonant level model\; where it turns out we can also calculat
e the full counting statistics exactly\, to good agreement with the numeri
cs. From the analytic properties of the full solution\, we show that the
system undergoes charge fractionalization when the bias voltage exceeds a
certain threshold.\n\n//indico.ictp.it/event/a1280/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1280/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Artificial
magnetic field for photons in a coupled cavity array"\n
DTSTART;VALUE=DATE-TIME:20120322T103000Z
DTEND;VALUE=DATE-TIME:20120322T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1278@ictp.it
DESCRIPTION:In this talk\, I will present some of our recent theoretical r
esults concerning photons in a coupled cavity array under a synthetic magn
etic field. A suitable coupling of the propagation and polarization degre
es of freedom introduces a geometrical phase for photons tunneling between
adjacent sites of a coupled cavity array\, which gives rise to the artifi
cial field. I will discuss the feasibility of observing strong magnetic f
ield effects in the optical spectra of realistic systems\, including the H
ofstadter butterfly spectrum. I will also touch on the observability of a
fractional quantum Hall effect for photons in these systems\, which is ex
pected to appear when effective interactions are induced between photons.\
n\n//indico.ictp.it/event/a1278/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1278/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical physics: "Avalanches in disordered
elastic systems"
DTSTART;VALUE=DATE-TIME:20120322T133000Z
DTEND;VALUE=DATE-TIME:20120322T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1286@ictp.it
DESCRIPTION:Disordered systems typically respond non-smoothly to external
driving. This manifests itself in Barkhausen noise\, earthquakes and aval
anches in granular media. A simple classical model which describes such p
henomena quite accurately is a particle driven by a spring on a Brownian r
andom-force landscape (also known as the ABBM model). I will present some
analytical results on statistics of avalanches in this model. I will the
n show how the ABBM model arises as the mean-field limit of a spatially ex
tended elastic interface in a disordered environment. In the end I will di
scuss the behavior below the upper critical dimension using renormalizatio
n-group methods.\n\n//indico.ictp.it/event/a1286/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a1286/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Form factors in fin
ite volume: Recent developments"\n
DTSTART;VALUE=DATE-TIME:20120327T100000Z
DTEND;VALUE=DATE-TIME:20120327T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1288@ictp.it
DESCRIPTION:A few years ago\, we initiated a research program to investiga
te the finite volume behaviour of matrix elements of local operators (form
factors) in quantum field theory. The testing ground of these ideas is p
rovided by integrable field theories such as the Lee-Yang\, Ising and sine
-Gordon models. The framework we developed can be used to provide a non-p
erturbative numerical method to determine form factors\, or to verify boot
strap form factor solutions against the field theory dynamics. It also se
rves as a theoretical tool to construct spectral expansions of correlatio
n functions in a thermal bath or in a boundary setting\, relevant to conde
nsed matter problems. In addition\, it gives us a way to address question
s of potential interest to lattice QCD. I plan to review the framework an
d its applications in a pedagogical manner\, and to discuss briefly the la
test developments.\n\n//indico.ictp.it/event/a1288/
LOCATION:SISSA\, Santorio Bldg.\,room 128
URL://indico.ictp.it/event/a1288/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Majorana f
ermions and subgap states in spinless p-wave superconducting wires"
DTSTART;VALUE=DATE-TIME:20120329T103000Z
DTEND;VALUE=DATE-TIME:20120329T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1291@ictp.it
DESCRIPTION:Spinless p-wave superconducting wires can be in a topological
phase in which they harbor Majorana bound states at their ends. Although
there are no known spinless p-wave superconductors in nature\, several rou
tes to the artificial creation of such systems have been proposed. In thi
s talk\, I will discuss how non-idealities in some of the proposed routes\
, such as potential disorder and deviations from a strict one-dimensional
limit\, affect the topological phase. In particular\, I'll discuss how th
e topological phase can persist at weak disorder or for multichannel wires
\, although some of the signatures of the presence of Majorana fermions ar
e obscured.\n\n//indico.ictp.it/event/a1291/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1291/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Local equilibration
and thermalization after a quantum quench"\n
DTSTART;VALUE=DATE-TIME:20120403T103000Z
DTEND;VALUE=DATE-TIME:20120403T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1296@ictp.it
DESCRIPTION:In this talk I will review some of our recent work on relaxati
on after a quantum quench. For dynamics generated by bosonic quadratic m
any-body Hamiltonians\, I will show under which conditions the state is lo
cally described by a Gaussian state in the long time limit. That is\, sub
systems converge to Gaussian states in trace norm for large times. These
Gaussian states can be given explicitly and there is no need for time aver
aging. In the second part of the talk\, I will introduce a setting in gen
eral spin systems for which thermalization and thermalization time can be
addressed: Fixing the spectrum of the Hamiltonian and picking its basis fr
om the Haar measure\, the time-dependent state may locally be described by
the maximally mixed state for almost all times in [0\,T]. Here\, T is al
gebraically small in the system size.\n\n//indico.ictp.it/event/a1296/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1296/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "A framework for coevolu
tion dynamics"
DTSTART;VALUE=DATE-TIME:20120405T153000Z
DTEND;VALUE=DATE-TIME:20120405T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12101@ictp.it
DESCRIPTION:We present a framework with minimal ingredients for the study
of coevolution in dynamical networks. This phenomenon is observed in many
complex systems in nature and consists of the coexistence of two processe
s on networks of interacting elements: node state change and rewiring of c
onnections between nodes. We consider that the process by which a node ch
anges its connections\, called rewiring\, and that the process by which a
node changes its state\, can have their own dynamics\, characterized by pr
obabilities Pr and Pc that express the time scales for each process\, resp
ectively.\nWe describe the process of rewiring in terms of two basic actio
ns: disconnection and reconnection between nodes\, both based on a mechani
sm of comparison of their states that in turn occur with different probabi
lities\, d and r. Then\, for a given rewiring process\, a coevolution mod
el corresponds to a specific coupling relation Pc = f(Pr). The collective
behavior of a coevolutionary system can be studied on any subspace of the
parameters Pr\, Pd\, d\, and r.\nAs an application\, for a voterlike node
dynamics we find that reconnections between nodes with similar states lea
d to network fragmentation. The critical boundaries for the onset of frag
mentation in networks with different properties are calculated on the spac
e (Pr\,Pc). The occurrence of a homogeneous connected phase and a fragme
nted phase in a network is predicted for diverse models\, and agreement is
found with some earlier results.\nWe also find regions of parameters wher
e modular structures with nodes in different states coexist for very long
times on one large\, connected network. Thus\, coevolution under some con
ditions can be seen as a mechanism for the emergence of communities observ
ed in many real networks.\n\n//indico.ictp.it/event/a12101/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12101/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:"Quantum phas
es of lattice bosons"
DTSTART;VALUE=DATE-TIME:20120405T103000Z
DTEND;VALUE=DATE-TIME:20120405T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1295@ictp.it
DESCRIPTION:In this talk I will discuss quantum states of bosonic lattice
systems and present benchmark results\, based on quantum Monte Carlo simul
ations\, for phase diagrams. These systems provide unique opportunities t
o explore interesting problems in strongly correlated physics\, providing
a wide variety of novel ground state phases (e.g. supersolids\, paired pha
ses\, Bose glass) and phase transitions\, with the possibility of compari
son with experiments. I will be focusing on the following two systems: \
ni) bosons in a disordered square lattice potential ii) bosons interacti
ng via dipolar interactions in a bilayer geometry. I will present the grou
nd state phase diagram of both systems as well as finite temperature resul
ts.\n\n//indico.ictp.it/event/a1295/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1295/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Bose statis
tics\, crystallization and quantum jamming"\n\n
DTSTART;VALUE=DATE-TIME:20120412T103000Z
DTEND;VALUE=DATE-TIME:20120412T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1294@ictp.it
DESCRIPTION:Indistinguishability of particles plays a major role in destab
ilizing crystalline order in Bose systems. \nIn this talk\, this effect w
ill be semi-quantitatively described in terms of damped quasi-particle mod
es\, and illustrated in the dual language of Feynman paths. A robust conf
irmation of this prediction is provided by means of first-principle simula
tions of dipolar bosons and bulk condensed helium-four. Two major implica
tions are that a) contrary to conventional wisdom\, zero-point motion al
one cannot prevent helium-four crystallization at low temperature\, at sat
urated vapour pressure\, and b) Bose statistics leads to quantum jamming
at finite temperature\, dramatically enhancing the metastability of super
fluid glasses. Only theoretical studies in which quantum statistics is fu
lly included can reliably address these issues.\n\n//indico.ictp.it/event/
a1294/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1294/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "On the quantum anne
aling of quantum mean-field models"\n
DTSTART;VALUE=DATE-TIME:20120417T103000Z
DTEND;VALUE=DATE-TIME:20120417T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12104@ictp.it
DESCRIPTION:In this talk I will present results obtained on fully-connecte
d mean-field models of quantum spins with p-body ferromagnetic interaction
s and a transverse field\, as a toy model for studying quantum annealing o
f disordered systems. For p=2 this corresponds to the quantum Curie-Weiss
model which exhibits a second-order phase transition\, while for p>2 the
transition is first order. We provide a refined analytical description of
both the static and dynamics properties of these models\, allowing us to
study the slow annealing from the pure transverse field to the pure ferrom
agnet (and vice versa) and discuss the effect of first-order phase transit
ion and spinodals on the residual excitation energy\, both on finite and e
xponentially divergent time-scales. We expect the general features that w
e found to be relevent for real disordered optimization problems.\n\n//ind
ico.ictp.it/event/a12104/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12104/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Pricing in
a complex financial market: Instability from local measures"\n\n\n
DTSTART;VALUE=DATE-TIME:20120419T103000Z
DTEND;VALUE=DATE-TIME:20120419T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12106@ictp.it
DESCRIPTION:Financial institutions need to price a huge number of instrume
nts every day\, and each of these instruments is generally priced accordin
g to models calibrated on financial data. The key issue\, however\, is th
at different institutions price the same instruments using different model
s and data\, i.e. different approximations. Such a heterogeneous picture
might lead to a system of inconsistent prices\, or\, in other words\, to a
rbitrage opportunities\, i.e. the emergence of strategies yielding a risk
free profit.\nIn this talk I will address this issue in the stylized frame
work of a random economy\, where the differences in the pricing models are
introduced as differences in the probability measures used to price diffe
rent financial instruments. Depending on the variability of such measures
and the number of assets\, the market may be either in an arbitrage free
state or in a state where arbitrage opportunities actually arise.\nThe pro
blem will be analyzed borrowing techniques from the statistical physics of
disordered systems: a general solution for the arbitrage region volume in
the model's parameter space will be derived and discussed\, eventually pr
oviding numerical evidence for some specific examples.\n\n//indico.ictp.it
/event/a12106/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12106/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Ultracold a
toms in optical lattices: Beyond the Hubbard model"\n\n
DTSTART;VALUE=DATE-TIME:20120426T103000Z
DTEND;VALUE=DATE-TIME:20120426T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12110@ictp.it
DESCRIPTION:We investigate the properties of ultra-cold atomic gases in op
tical lattices\, which we use as a toy-system to explore the intriguing pr
operties of strongly correlated quantum many-body systems in periodic pote
ntials.\nIn this work\, we address the regime of weak and intermediate opt
ical lattices\, where the conventional description in terms of the single
band Hubbard model is not reliable.\nIn the case of bosonic atoms\, we emp
loy a novel hybrid Monte Carlo technique which allows to simulate the supe
rfluid to insulator transition in continuous space\, thus going beyond the
single-band approximation. For fermions\, we apply Kohn-Sham Density Func
tional Theory (DFT)\, which is the most powerful computational tool routin
ely used in material science to perform electronic structure simulations.
In this work\, we use a new\nenergy-density functional for dilute atomic F
ermi gases with short-range interactions\, as opposed to the Coulomb inter
action in electronic systems. The first results based on a local spin-dens
ity approximation show evidence of a ferromagnetic phase due to the strong
repulsive inter-species interactions close to a Feshbach resonance\, and
of anti-ferromagnetic order at half filling.\nWe will discuss how the deve
lopment of DFT for ultracold Fermi gases can form a strong link between ma
terials science and atomic physics.\n\n//indico.ictp.it/event/a12110/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12110/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Fundamental
aspects of transport in nanoscale systems and ultra-cold atoms"\n\n
DTSTART;VALUE=DATE-TIME:20120503T103000Z
DTEND;VALUE=DATE-TIME:20120503T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12113@ictp.it
DESCRIPTION:I will discuss some of the most basic questions in fermionic a
nd bosonic transport\, such as the conditions for the existence of a stead
y-state current\, its uniqueness\, the role of interactions and spin stati
stics\, its entanglement entropy\, etc. This will lead me to introduce an
alternative viewpoint to conduction - the micro-canonical formalism of tr
ansport - which is ideal to study the above issues [1]. I will point out t
he similarities and differences with the widely used Landauer formalism\,
and advance a series of predictions that can be verified by loading ultra-
cold atoms into artificial optical lattices.\n\n[1] M. Di Ventra\, Electri
cal Transport in Nanoscale Systems (Cambridge University Press\, 2008).\n\
n//indico.ictp.it/event/a12113/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12113/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Product of free ide
ntically distributed R-diagonal random matrices"\n
DTSTART;VALUE=DATE-TIME:20120508T103000Z
DTEND;VALUE=DATE-TIME:20120508T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12116@ictp.it
DESCRIPTION:We show that the eigenvalue density of the product of n identi
cally distributed R-diagonal random matrices from a given matrix ensemble
is equal to the eigenvalue density of n-th power of a single matrix from t
his ensemble in the limit of infinite matrix size. Using this observation
one can derive the limiting eigenvalue density of the product of n indepen
dent identically distributed matrices for non-Hermitian matrix ensembles w
ith invariant measures. We discuss two examples: the product of n Girko-Gi
nibre matrices and the product of n truncated unitary matrices.\n\n//indic
o.ictp.it/event/a12116/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12116/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"Current rec
tification in ac-driven Hamiltonian systems: \nFrom classical to quantum r
atchets"\n
DTSTART;VALUE=DATE-TIME:20120510T103000Z
DTEND;VALUE=DATE-TIME:20120510T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12115@ictp.it
DESCRIPTION:I will start with a short introduction into the ratchet proble
m by using a simple model of a particle in an ac-driven periodic potential
\, give a basic on the symmetry analysis\, and discuss the mechanisms of
current rectification in the Hamiltonian limit. Theoretical findings are
illustrated with the experimental results obtained with cold atoms and opt
ical potentials. Next I will turn to the quantum limit\, specify quantum
features of ac-driven Hamiltonian ratchets\, and review the recent experi
mental realization of the quantum flashing/tilting ratchet with BEC of Rub
idium atoms. Finally\, the performance of quantum ratchets in the presence
of decoherence will be addressed.\n\n//indico.ictp.it/event/a12115/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12115/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Anisotropic Ginzbur
g-Landau and Lawrence-Doniach models for ultracold Fermi gases"\n
DTSTART;VALUE=DATE-TIME:20120515T100000Z
DTEND;VALUE=DATE-TIME:20120515T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12121@ictp.it
DESCRIPTION:I will introduce the anisotropic Ginzburg-Landau and Lawrence-
Doniach models that describe layered superfluids and superconductors\, inc
luding the large class of high-Tc superconductors. I will show how these e
quations apply to ultracold Fermi gases in optical lattices. This allows o
ne to find the temperature of the 3D-2D crossover where the bulk superflui
d decouples into uncorrelated 2D systems. I will show how this behaviour c
an be explored in ultracold gases\, and how to reproduce the physics of la
yered superconductors. I will show how the optical lttice affects the gas
differently across the BEC-BCS crossover and that the most interesting beh
aviour is found near the unitary limit.\n\n//indico.ictp.it/event/a12121/
LOCATION:SISSA\, Santorio Bldg.\, 1st floor- Room 128
URL://indico.ictp.it/event/a12121/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"Dilute Bose
gas in quasi-2D correlated random potentials"\n
DTSTART;VALUE=DATE-TIME:20120517T103000Z
DTEND;VALUE=DATE-TIME:20120517T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12123@ictp.it
DESCRIPTION:Laser speckles provide a unique possibility to create fully co
ntrolled two-dimensional disorder potentials for neutral atoms. This type
of disorder has exponential probability distribution and finite spatial
correlation length. In this talk\, I shall present our recent results on
the superfluidity and Bose-Einstein condensation of interacting bosons in
the presence of the laser speckles at zero temperature obtained using diff
usion Monte Carlo method in continuum as well as Gross-Pitaevskii equation
and Bogolubov theory.\n\n//indico.ictp.it/event/a12123/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12123/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Impact of meta-orde
r in the Minority Game"
DTSTART;VALUE=DATE-TIME:20120522T103000Z
DTEND;VALUE=DATE-TIME:20120522T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12131@ictp.it
DESCRIPTION:We study the market impact of a meta-order in the framework of
the Minority Game. This amounts to studying the response of the market wh
en introducing a trader who buys or sells a fixed amount h for a finite ti
me T. This perturbation introduces statistical arbitrages that traders exp
loit by adapting their trading strategies. The market impact depends on th
e nature of the stationary state: we find that the permanent impact is zer
o in the unpredictable (information efficient) phase\, while in the predic
table phase it is non-zero and grows linearly with the size of the meta-or
der. This establishes a quantitative link between information efficiency a
nd trading efficiency (i.e. market impact). By using statistical mechanics
methods for disordered systems\, we are able to fully characterize the re
sponse in the predictable phase\, to relate execution cost to response fun
ctions and obtain exact results for the permanent impact.\n\n//indico.ictp
.it/event/a12131/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12131/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Superfluidity and locali
zation in bosonic glasses"\n
DTSTART;VALUE=DATE-TIME:20120523T150000Z
DTEND;VALUE=DATE-TIME:20120523T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12132@ictp.it
DESCRIPTION:Bosons can exhibit superfluid\, density-ordered\, and even gla
ssy phases. It is interesting to ask whether superfluidity and density ord
er can coexist\, which requires the simultaneous breaking of two symmetrie
s with competing order parameters. We have analyzed a fully connected mod
el of frustrated bosons\, which indeed exhibits such an intermediate phase
. Its hallmarks are anticorrelations between the local order parameters\,
and a non-monotonous superfluid order parameter as a function of T.\n\nTo
study transport\, we extend this fully connected model to a Bethe lattice
with finite but large connectivity. While thermodynamic properties are i
nsensitive to quantum fluctuations\, the latter play an important role for
the dynamics in the glassy insulator. The glassy order is shown to affec
t significantly the superfluid-insulator transition\, which is exactly sol
vable. In the glassy insulator we find a finite mobility edge for bosonic
excitations\, which does not close upon approaching the superfluid transi
tion.\n\n//indico.ictp.it/event/a12132/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12132/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Freezing tr
ansition: From 1/f landscapes to characteristic polynomials of random matr
ices and the Riemann zeta-function"
DTSTART;VALUE=DATE-TIME:20120524T103000Z
DTEND;VALUE=DATE-TIME:20120524T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12126@ictp.it
DESCRIPTION:I will argue that the freezing transition scenario\, previousl
y conjectured to take place in Statistical Mechanics of 1/f-type Random E
nergy Model\, governs\, after reinterpretation\, the value distribution of
the maximum of the modulus of the characteristic polynomials of large ran
dom unitary (CUE) matrices. I then conjecture that the results extend to t
he large values taken by the Riemann zeta-function over stretches of the c
ritical line s=1/2+it of constant length\, and present the results of nume
rical computations of the large values of \\zeta(1/2+it). The main purpose
is to draw attention to possible connections between the statistical mech
anics of random energy landscapes\, random matrix theory\,and the theory o
f the Riemann zeta function.\n\nThe presentation will be based on the join
t work with G.Hiary and J.P. Keating: Phys. Rev. Lett. 108 \, 170601 (2012
)\n\n//indico.ictp.it/event/a12126/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12126/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Entanglement entrop
y of one-dimensional quantum systems"\n
DTSTART;VALUE=DATE-TIME:20120604T130000Z
DTEND;VALUE=DATE-TIME:20120604T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12139@ictp.it
DESCRIPTION:In this talk I will review some of the work on Entanglement En
tropy that I have carried out in collaboration with various authors since
2007. For general 1d Quantum Field Theories\, the central objects are Twis
t Fields whose correlation functions are directly related to the entropy.
In the context of Quantum Spin Chains\, Twist Operators play a similar rol
e and products thereof can be related to the twist fields in the continuou
s limit.\nOnce the entropy has been expressed in terms of correlation func
tions of these fields (or operators on the chain) one may exploit the powe
rful tools of integrable quantum models to establish new results. We may s
tudy both the short- and long-distance behaviours of the entropy in variou
s kinds of theories\, study the matrix elements of twist fields (or twist
operators) on their own right\, or investigate the features of other corre
lation functions involving the twist field. In my talk I will try to touch
on the main results we have obtained when addressing some of these proble
ms.\n\n//indico.ictp.it/event/a12139/
LOCATION:SISSA\, Santorio Bldg\, Room 128
URL://indico.ictp.it/event/a12139/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter seminar: " Geometry and incompre
ssibility in \nthe fractional quantum Hall effect"\n
DTSTART;VALUE=DATE-TIME:20120604T150000Z
DTEND;VALUE=DATE-TIME:20120604T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12142@ictp.it
DESCRIPTION:Incompressibility in the fractional QHE is identified as a var
iant of Mott-Hubbard incompressibility\, where additional electrons are ex
cluded from a region occupied by a “composite boson” of p electrons in
q orbitals (or p electrons with q “attached flux quanta”) at Landau-l
evel filling \\nu = p/q. The new ingredient is that the shape of this “e
xclusion zone” is described by an intrinsic ”unimodular” (determinan
t = 1) spatial metric tensor field g_{ab}(x\,t)\, that is a true dynamical
variable that fluctuates about the shape that minimizes the correlation e
nergy of the FQH state. It emerges that the electron density is pinned to
the combination peB-\\hbar s K_g rather than to the magnetic flux density
B alone\, where K_g is the gaussian curvature of the metric\, and s is a
new characteristic topologically-quantized ”guiding-center spin” relat
ed to the so-called ”shift” of the FQH state. This metric can be seen
in the Laughlin state as a explicit variational parameter that has remaine
d hidden for the past thirty years because of a fundamental misinterpretat
ion of the Laughlin state as a ”lowest Landau level Schrödinger wavefun
ction”: (in fact it is a guiding-center coherent state that does not dep
end on which Landau level is partially filled).\n\n//indico.ictp.it/event/
a12142/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12142/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Star-figures in con
formal loop ensembles: The stress tensor and some of its descendants"\n
DTSTART;VALUE=DATE-TIME:20120605T103000Z
DTEND;VALUE=DATE-TIME:20120605T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12140@ictp.it
DESCRIPTION:Consider the clusters of same-sign spins in the Ising model. I
n the scaling limit at criticality\, their boundaries become (countably) i
nfinitely many loops that don't intersect\, and the Boltzman weight become
s a probability measure for these loop configurations. Conformal loop ense
mble (CLE) is a one-parameter family of measures on such loop configuratio
ns with properties of locality and conformal invariance. It includes the m
easure obtained from the scaling limit of the critical Ising model\, but a
lso measures corresponding to all central charges between 0 and 1. It is b
elieved that this loop description contains all the information of the usu
al local-operator CFT\, in particular about minimal models. In this talk I
will tell you how to represent the stress tensor and some of its descenda
nts as random variables in CLE. The random variables essentially measure h
ow likely it is that loops be separated by some specific closed curves tha
t look like stars (with a bit of imagination)\; these stars are made to "r
otate" at various angular velocities. It is interesting that the star-figu
re random variables in principle give definitions for the associated stres
s-tensor descendants even beyond CFT. This talk will be very elementary: I
'll introduce all necessary notions\, and if time permits I will give you
an idea of how the proof works.\n\n//indico.ictp.it/event/a12140/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12140/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Holographic
insights into non-equilibrium quantum fields'
DTSTART;VALUE=DATE-TIME:20120607T103000Z
DTEND;VALUE=DATE-TIME:20120607T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12141@ictp.it
DESCRIPTION:Understanding dynamical phenomena in strongly coupled systems
is an interesting challenge. While the quantum dynamics has been tackled
on its own by a variety of techniques developed over the years\, an import
ant window into such physics is provided by the holographic AdS/CFT corres
pondence\, which effectively converts the quantum problem into a classical
master field dynamics in a suitable limit. I will review progress made o
ver the last few years using AdS/CFT in shedding light in out-of equilibri
um dynamics. Focus will be on elucidating the hydrodynamic regime of inter
acting field theories and issues regarding thermalization\, etc.\, which w
ill holographically be related to the behaviour of black holes in the dual
description.\n\n//indico.ictp.it/event/a12141/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12141/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Colloquium on Condensed Matter Physics: "Mott loc
alization transition: From semiconductors to supersolids"\n
DTSTART;VALUE=DATE-TIME:20120612T150000Z
DTEND;VALUE=DATE-TIME:20120612T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12146@ictp.it
DESCRIPTION:The Mott metal-insulator transition is 60 years old. Despite m
ajor recent progress with the help of DMFT it retains mysteries. Ancient e
xperiments on electron-hole droplets in germanium in silicon display a fir
st order transition\, similar to that found in the half filled fermion Hub
bard model. What is the corresponding order parameter? How does one evolve
from that first order regime to the simple 1949 Mott picture? The issue r
emains open.\nThe recent discovery of supersolids extends the Mott transit
ion to Bose liquids. A Bose Hubbard model with integer filling has a choic
e between superfluidity or localization at zero temperature\, with a secon
d order transition: as usual bosons are simpler than fermions! In practice
we want a real crystal where weak crystallization is due to freezing of s
oft phonon modes: the challenge is to introduce localization into such a s
pontaneous solid.\nThe seminar will try to put these questions in perspect
ive. If time allows the issue of supersolidity in He4 will be discussed in
some detail. It seems to occur only in defects \, but it opens a whole n
ew field.\n\n//indico.ictp.it/event/a12146/
LOCATION:SISSA\, Santorio Bldg.\, Room 128 (first floor)
URL://indico.ictp.it/event/a12146/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Top eigenvalue of C
auchy random matrices"
DTSTART;VALUE=DATE-TIME:20120626T103000Z
DTEND;VALUE=DATE-TIME:20120626T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12150@ictp.it
DESCRIPTION:I present analytical results on the distribution of the larges
t eigenvalue for random matrices of the Cauchy type.\nMatrices belonging t
o this ensemble i) have a rotationally invariant weight\, and ii) display
a spectral density having support on the full real axis\, which decays as
a power law for x\\to\\pm\\infty.\nThe distribution exhibits a central reg
ime that is governed by a scaling function (analogous to the Tracy-Widom d
istribution)\, flanked on both sides by large deviation tails. The corres
ponding rate functions are computed analytically using a mapping to a Coul
omb gas system with constraints. The analytical results are corroborated b
y numerical simulations with excellent agreement.\n\n//indico.ictp.it/even
t/a12150/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12150/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar: "The mathematics of poker: Game theory" (Part I)
DTSTART;VALUE=DATE-TIME:20120709T140000Z
DTEND;VALUE=DATE-TIME:20120709T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12154@ictp.it
DESCRIPTION:Game theory is relatively modern branch of mathematics with ma
ny applications\, for instance\, in economics\, biology and poker. We'll
describe some basic models of game theory\, in particular exactly solvable
games that can be used as toy model of poker situations: 'game of chicken
'\, the 'AKQ game' (in its basic Borel and Von Neumann versions\, plus som
e non trivial extensions)\, the [0\,1]-game\, and the No Limit Holdem Jam-
or-Fold heads up game (both in cash game and tournaments). The two semina
rs will not assume any previous knowledge in game theory or poker.\n\n//in
dico.ictp.it/event/a12154/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12154/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar: "The mathematics of poker: Game theory" (Part II)
DTSTART;VALUE=DATE-TIME:20120710T090000Z
DTEND;VALUE=DATE-TIME:20120710T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12155@ictp.it
DESCRIPTION:Game theory is relatively modern branch of mathematics with ma
ny applications\, for instance\, in economics\, biology and poker. We'll
describe some basic models of game theory\, in particular exactly solvable
games that can be used as toy model of poker situations: 'game of chicken
'\, the 'AKQ game' (in its basic Borel and Von Neumann versions\, plus som
e non trivial extensions)\, the [0\,1]-game\, and the No Limit Holdem Jam-
or-Fold heads up game (both in cash game and tournaments). The two semina
rs will not assume any previous knowledge in game theory or poker.\n\n//in
dico.ictp.it/event/a12155/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12155/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Deciding about manu
scripts: The dynamics of refereeing"\n
DTSTART;VALUE=DATE-TIME:20120710T103000Z
DTEND;VALUE=DATE-TIME:20120710T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12156@ictp.it
DESCRIPTION:How a referee writes a report is interesting for two main reas
ons. The general one is that it is an example of how humans perform tasks\
, and in this it is similar to maintaining correspondence\, whether done b
y letters\, email\, or messaging systems. Here recently debates have raged
about whether such activity leads - perhaps intrinsically - to power-law
statistics and how that would follow from priority queue -type models. The
second\, not necessarily less important one\, is that it gives us insight
into how science\, journals\, and peer review works. Here we discuss empi
rical data from two physics journals\, and what can be distilled from the
data. We present a simple "many tasks" model\, which fits the data fairly
well. Conclusions are presented about both the issues\, and in particular
about refereeing as seen in the light of both the data and models.\n\n//in
dico.ictp.it/event/a12156/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12156/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Electron gl
ass"\n
DTSTART;VALUE=DATE-TIME:20120718T150000Z
DTEND;VALUE=DATE-TIME:20120718T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12242@ictp.it
DESCRIPTION:An electron glass (EG) is a disordered film with localized ele
ctronic states and hopping conduction. It has a long time relaxation (hou
rs and days)\, that usually manifests itself in the slow change of the hop
ping conduction. Moreover\, they may have a memory. Namely\, conductivity
of the film as a function of the electron density memorizes the density at
which it has been cooled. Disordered films of InxO [1]\, films granulated
by gold [2] or aluminum [3] are examples of EG’s. Important low energy
excitations in such a system can be classified as single electron excitati
ons that feature the so-called Coulomb Gap\, and pair excitations that are
random dipoles [4]. I argue that the polarization of dipole interactions
leads to a “polarization catastrophe” due to interaction of these exci
tations. As a result dipoles form a dipole glass [5]. I propose that this
is at the basis of glassy properties of the system. The width of the “me
mory dip” is calculated.\n\n1. M Ben-Chorin\, D. Kowal\, and Z. Ovadyahu
\, Phys. Rev. B44\, 342 (1991).\n2. C.J. Adkins et al. J. Phys. C17\, 4693
(1984).\n3. T. Grenet\, Eur. Phys. J. B32\, 275 (2003).\n4. A.L. Efros an
d B.I. Shklovskii\, J. Phys. C8\, L 49 (1975).\n5. B.E. Vugmeister and M.D
. Glinchuk\, Rev. Modern Phys. 62\, 993 (1990).\n\n//indico.ictp.it/event/
a12242/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12242/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Quasi-equilibrium in gl
assy dynamics: An algebraic view"\n\n
DTSTART;VALUE=DATE-TIME:20120719T103000Z
DTEND;VALUE=DATE-TIME:20120719T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12243@ictp.it
DESCRIPTION:We study a chain of identical thermodynamic systems in a const
rained equilibrium where each bond of the chain is forced to remain at a p
reassigned distance to the previous one. We apply this description to gla
ssy systems in the limit of long chain where each bond is close to the pre
vious one. We show that in specific conditions this pseudo-dynamic proces
s can formally describe real relaxational dynamics the long time. In part
icular\, in mean field spin glass models we can recover in this way the eq
uations of Langevin dynamics in the long time limit at the dynamical trans
ition temperature and below. We interpret the formal identity as an evide
nce that in these situations the configuration space is explored in a quas
i-equilibrium fashion.\nOur general formalism\, that relates dynamics to e
quilibrium puts slow dynamics in a new perspective and opens the way to th
e computation of new dynamical quantities in glassy systems.\n\n//indico.i
ctp.it/event/a12243/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12243/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical physics: "Diffusion with stochasti
c resetting"
DTSTART;VALUE=DATE-TIME:20120724T103000Z
DTEND;VALUE=DATE-TIME:20120724T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12249@ictp.it
DESCRIPTION:We study a simple model of search where the searcher undergoes
normal diffusion\, but once in a while resets to its initial starting poi
nt stochastically with rate r. The effect of a finite resetting rate r
turns out to be rather drastic. It leads to finite mean search time whic
h\, as a function of r\, has a minimum at an optimal resetting rate r_c.
\nThis makes the search process efficient.\nWe then generalize this model
to study multiple searchers.\nResetting alters fundamentally the late time
decay of the survival probability of a stationary target when there are m
ultiple searchers: while the typical survival probability decays exponenti
ally with time\, the average decays as a power law with an exponent depend
ing continuously on the density of searchers. We also consider various ge
neralisations of this simple model.\n\nRefs:\n\nM.R. Evans and S.N. Majumd
ar\,\n"Diffusion with Stochastic Resetting"\, Phys. Rev. Lett. 106\, 16060
1 (2011).\n\nM.R. Evans and S.N. Majumdar\, "Diffusion with Optimal Resett
ing"\, J. Phys. A-Math. & Theor. 44\, 435001 (2011).\n\n//indico.ictp.it/e
vent/a12249/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12249/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Colloquium on Condensed Matter physics: "X-ray ab
sorption spectra of water and ice"
DTSTART;VALUE=DATE-TIME:20120725T150000Z
DTEND;VALUE=DATE-TIME:20120725T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12250@ictp.it
DESCRIPTION:X-ray absorption spectroscopy (XAS) is a powerful tool to inve
stigate matter at the molecular scale\, but requires a good theory of the
excitation process as a prerequisite to a consistent experimental interpre
tation. New XAS calculations\, based on the GW approximation for the self
-energy of the excited quasi-electron in presence of a static core hole\,
are in good agreement with experiment in liquid water\, hexagonal (Ih) ice
\, high pressure ice VIII\, and the two amorphous ice forms LDA (low densi
ty amorphous ice) and HDA (high density amorphous ice). Good models of di
sorder are essential to achieve experimental agreement\, and disorder asso
ciated to the quantal dynamics of the nuclei plays an important role. Ana
lysis of the spectral features yields valuable information on the unifying
aspects of short- and intermediate-range order in these systems.\n\n//ind
ico.ictp.it/event/a12250/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12250/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Duality of
weak and strong scatterer in Luttinger liquid coupled to massless bosons"
DTSTART;VALUE=DATE-TIME:20120817T103000Z
DTEND;VALUE=DATE-TIME:20120817T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12262@ictp.it
DESCRIPTION:We study[1\, 2] electronic transport through a Luttinger liqui
d with an embedded weak scatterer (WS) or weak link (WL) in the presence o
f the electron coupling to one-dimensional massless bosons (phonons). We h
ave found that for an arbitrary fixed strength of boson scattering by the
impurity the scaling dimensions of the conductance in the WS and WL cases
obeys the duality condition\, ∆WS∆WL = 1\, established for the standar
d Luttinger liquid [3] (i.e. in the absence of the additional coupling). O
n the other hand\, with the strength of both fermion and boson scattering
by impurity changing from the WS to the WL limit\, the system has a rich p
hase diagram with a metal-insulator transition as a function of a bare bac
kscattering amplitude. The transition exists in a certain interval\, defin
ed by the relative strength of the electron-electron and electron-boson co
upling and the ratio of Fermi to sound velocities.\n\n[1] A. Galda\, I. V.
Yurkevich\, and I. V. Lerner\, Phys. Rev. B 83\, 041106 (2011)\; EPL 93\,
17009 (2011). \n[2] I. V. Yurkevich\, A. Galda\, O. M. Yevtushenko\, and
I. V. Lerner\, to be published (2012). \n[3] C. L. Kane and M. P. A. Fishe
r\, Phys. Rev. Lett. 68\, 1220 (1992)\; Phys. Rev. B 46\, 15233–15262 (1
992).\n\n//indico.ictp.it/event/a12262/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12262/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Long range interact
ions for the critical Ising model"\n
DTSTART;VALUE=DATE-TIME:20120918T100000Z
DTEND;VALUE=DATE-TIME:20120918T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12277@ictp.it
DESCRIPTION:In this talk I will report on recent results in the study of f
erromagnetic long range interactions for the Ising model. After recalling
the classical results for this class of interactions\, I will present res
ults for a numerical study in two dimensions in the intermediate regime an
d the connection with the short range regime. Next I will discuss the rel
evance of the long range interaction versus the short range interaction.
Finally\, I will present a proposal for computing the influence of the lo
ng-range interactions as a dimensional change for a short range model and
compare with the results of the numerical simulations.\n\n//indico.ictp.it
/event/a12277/
LOCATION:SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a12277/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Quantum phases of s
oft core bosons with Rydberg gases"
DTSTART;VALUE=DATE-TIME:20120924T133000Z
DTEND;VALUE=DATE-TIME:20120924T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12281@ictp.it
DESCRIPTION:Motivated by recent experimental efforts to realize quantum ph
ases of matter with cold atomic Rydberg gases\, I will discuss the phase d
iagram and excitation spectrum of supersolids in a two dimensional bosonic
system with soft-core interactions.\nPrevious works [1] showed an excepti
onal agreement between Monte Carlo simulations and a numerical mean-field
approach. I will present a variational analysis of the Gross-Pitaevskii e
quation with a non-local interaction term and show that we can quantitativ
ely reproduce the superfluid-supersolid transition at finite interaction s
trength in agreement with Monte Carlo results. We then test the validity
of this mean-field analysis perturbing the ground state wave function and
looking at the spectrum of the corresponding Bogoliubov equations. This a
pproach provides an intuitive physical insight to the low energy dynamics
of the system and is validated through the comparison of our findings with
recent Monte Carlo simulations [2].\n\nReferences\n\n[1] N. Henkel\, F. C
inti\, P. Jain\, G. Pupillo\, T. Pohl\, Phys. Rev. Lett. 108\, 265301 (201
2)\n[2] S. Saccani\, S. Moroni\, and M. Boninsegni\, Phys. Rev. Lett. 108\
, 175301 (2012).\n\n//indico.ictp.it/event/a12281/
LOCATION:SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a12281/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Entanglement entrop
y in long-range harmonic oscillators"\n
DTSTART;VALUE=DATE-TIME:20120925T103000Z
DTEND;VALUE=DATE-TIME:20120925T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12282@ictp.it
DESCRIPTION:We will first present a pedagogical introduction to entangleme
nt entropy. Then we will define long-range harmonic oscillators as the bui
lding block of long-range interacting bosonic systems. Using hamiltonian t
echnique we will calculate the Von Neumann and Renyi entanglement entropy
for this system. Different kind of boundary conditions as well as massive
harmonic oscillators will be discussed.\n\nReferences\n\nM. Ghasemi Nezhad
haghighi\, M. A. Rajabpour\, arXiv:1209.1883\n\n//indico.ictp.it/event/a12
282/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12282/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Colloquium on Condensed Matter Physics: "Actual p
roblems of physics of cryocrystals"
DTSTART;VALUE=DATE-TIME:20121003T153000Z
DTEND;VALUE=DATE-TIME:20121003T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12287@ictp.it
DESCRIPTION:JOINT ICTP/SISSA\n\nCOLLOQUIUM\n\nON CONDENSED MATTER PHYSICS\
n\n\n\n\nWednesday\, 3 October - 4:30 p.m.\n\n\n\n\nLuigi Stasi Seminar R
oom\nICTP Leonardo Building (1st floor)\n\n\n\nYuri A. FREIMAN\n( Verkin I
nstitute for \nLow Temperature Physics & Engineering\, Kharkov )\n\n\n\n\n
" Actual problems of physics of cryocrystals"\n\n\n\n\nAbstract\n\nGaseous
at room temperature or low pressures and solid at low temperatures or hig
h pressures\, cryocrystals (rare gas solids\, solid hydrogens\, oxygen\, n
itrogen\, etc.) are one of the richest areas of contemporary physics resea
rch. As the simplest materials resembling solid-state models\, they are th
e best testing ground for studying the physics of condensed matter. A sho
rt review will be given of new results and actual problems of physics of c
ryocrystals which were under discussion at the recent conference Cryocry
stals 2012 (Odessa\, Ukraine\, September 2 – 8\, 2012).\n\n//indico.ict
p.it/event/a12287/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12287/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Glassy phys
ics\, excitations\, and avalanches in electron glasses"\n
DTSTART;VALUE=DATE-TIME:20121018T103000Z
DTEND;VALUE=DATE-TIME:20121018T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12293@ictp.it
DESCRIPTION:Electron glasses are disordered systems of localized electrons
with long-range Coulomb interaction\, as found at low temperature in dope
d semiconductors\, amorphous semiconductors\, and granular metals.\nExperi
ments on several of these systems demonstrate a very slowly relaxing condu
ctivity and striking non-equilibrium effects that suggest glassy physics o
f electronic origin.\nI will review our recent studies of the electron gla
ss problem\, mostly based on large-scale numerical computations\, addressi
ng the existence of a thermodynamic glass phase\, the shape of the Coulomb
gap in the single-particle density of states (which affects the variable-
range hopping conductivity)\, and the statistics of the charge avalanches
induced by a small perturbation of the system. Throughout the talk I will
emphasize analogies and differences between electron glasses and spin gla
sses.\n\n//indico.ictp.it/event/a12293/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12293/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA/Dipartimento di Fisica Colloquium on Condensed Ma
tter physics: "First coherent radiation from the \nFERMI@Elettra free elec
tron laser: Status report and plan for the first experiments"\n
DTSTART;VALUE=DATE-TIME:20121024T130000Z
DTEND;VALUE=DATE-TIME:20121024T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12295@ictp.it
DESCRIPTION:The new free-electron laser (FEL) source FERMI@Elettra seeded
at 260 nanometers with an external laser has produced the first coherent e
mission from the FEL-1 undulator chain tuned at wavelengths of 65 nanomete
rs (fourth harmonic of the seed laser) and 43 nanometers (sixth harmonic).
This marks the first successful operation of FERMI@Elettra in its planne
d configuration\, i.e.\, as a next-generation seeded free-electron laser s
ource. Over the coming months the commissioning team will continue to imp
rove the overall performance of the system and the light will be provided
to the first experimental programs. In the meantime the construction of t
he FEL-2 will be completed and the commissioning started. \nHere I will pr
esent the scientific program for the first experiments along with the stra
tegic road map for the commissioning of the entire facility and future upg
rades.\n\n//indico.ictp.it/event/a12295/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12295/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar: " Effect of short-range interactions on the\nquan
tum critical behavior of spinless fermions on the honeycomb lattice "\n
DTSTART;VALUE=DATE-TIME:20121031T150000Z
DTEND;VALUE=DATE-TIME:20121031T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12304@ictp.it
DESCRIPTION:I present a functional renormalization group investigation of
an Euclidean three-dimensional matrix Yukawa model with U(N) symmetry\, wh
ich describes N = 2 Weyl fermions that effectively interact via a short-ra
nge repulsive interaction. This system relates to an effective low-energy
theory of spinless electrons on the honeycomb lattice and can be seen as
a simple model for suspended graphene. A continuous phase transition is f
ound which is characterized by large anomalous dimensions both for the fer
mions and composite degrees of freedom. The critical exponents define a n
ew universality class distinct from Gross-Neveu type models\, typically co
nsidered in this context.\n\n//indico.ictp.it/event/a12304/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12304/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Real space entangle
ment spectra \nfor large systems"\n
DTSTART;VALUE=DATE-TIME:20121106T100000Z
DTEND;VALUE=DATE-TIME:20121106T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12309@ictp.it
DESCRIPTION:I will present a way to calculate the Particle Entanglement Sp
ectrum (PES) and Real Space Entanglement Spectrum (RSES) of multi-particle
systems from their real space wave functions. Our technique allows numeri
cal calculations for much larger systems than were previously feasible. I
will illustrate the method with results on the RSES and PES for the Laughl
in and Jain composite fermion states and for the Moore-Read state at filli
ng nu=5/2 \, for system sizes up to 70 particles.\n\n//indico.ictp.it/eve
nt/a12309/
LOCATION: SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a12309/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Local atom-
number fluctuations in quantum gases at finite temperature"\n\n
DTSTART;VALUE=DATE-TIME:20121108T103000Z
DTEND;VALUE=DATE-TIME:20121108T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12308@ictp.it
DESCRIPTION:We investigate the number fluctuations in small cells of quant
um gases pointing out important deviations from the thermodynamic limit fi
xed by the isothermal compressibility. Both quantum and thermal fluctuati
ons in weakly as well as highly compressible fluids are considered. For t
he two-dimensional (2D) superfluid Bose gas we find a significant quenchin
g of fluctuations with respect to the thermodynamic limit\, in agreement w
ith recent experimental findings. An enhancement of the thermal fluctuati
ons is instead predicted for the 2D dipolar superfluid Bose gas\, which be
comes dramatic when the size of the sample cell is of the order of the wav
elength of the rotonic excitation induced by the interaction.\n\n//indico.
ictp.it/event/a12308/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12308/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: " MicroRNAs: A selec
tive\, post-transcriptional channel of communication between RNAs "
DTSTART;VALUE=DATE-TIME:20121113T103000Z
DTEND;VALUE=DATE-TIME:20121113T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12313@ictp.it
DESCRIPTION:It has recently been suggested that the competition for a fini
te pool of microRNAs (miRNA) gives rise to effective interactions among th
eir common targets (competing endogenous RNAs or ceRNAs) that could prove
to be crucial for post-transcriptional regulation (PTR). I shall discuss a
minimal model of PTR where the emergence and the nature of such interacti
ons can be characterized in detail at steady state. Sensitivity analysis s
hows that binding free energies and repression mechanisms are the key ingr
edients for the cross-talk between ceRNAs to arise. Interactions emerge in
specific ranges of repression values\, can be symmetrical (one ceRNA infl
uences another and vice-versa) or asymmetrical (one ceRNA influences anoth
er but not the reverse) and may be highly selective\, while possibly limit
ed by noise. However\, I will also show that non-trivial correlations amon
g ceRNAs can emerge in experimental readouts even in absence of miRNA-medi
ated cross-talk simply due to transcriptional fluctuations.\n\n//indico.ic
tp.it/event/a12313/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12313/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Non-equilib
rium steady states of boundary-driven open quantum chains"\n
DTSTART;VALUE=DATE-TIME:20121115T103000Z
DTEND;VALUE=DATE-TIME:20121115T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12316@ictp.it
DESCRIPTION:We will discuss a general non-equilibrium setup by which one c
an approach the quantum transport problem in one dimension. One considers
a strongly interacting quantum chain with fully coherent bulk dynamics an
d driven out of equilibrium in terms of Lindblad dissipators which only ac
t on degrees of freedom near the boundary\, i.e. at the ends of the chain.
The non-equilibrium state carrying the physical currents is then approxi
mated as the steady state of the corresponding Markovian master equation.\
nIn this talk I will describe several interesting results which have recen
tly been obtained along these lines. Firstly\, using numerical methods ins
pired by the density matrix renormalization group\, one can - quite remark
ably - find examples of diffusive transport in clean\, and even Bethe-ansa
tz integrable\, strongly interacting systems (at high-temperature near-equ
ilibrium conditions)\, such as the Heisenberg XXZ spin 1/2 chain and the o
ne-dimensional fermionic Hubbard model.\nSecondly\, under far from equilib
rium conditions\, one can find several exact analytical solutions which de
scribe steady states with anomalous transport properties. For example\, i
n the Heisenberg XXZ chain under extreme boundary driving we show that the
steady-state density operator of a finite system of size N is -- apart fr
om a normalization constant -- a polynomial of degree 2N-2 in the coupling
constant. The perturbative (weak coupling) version of our ansatz is used
to derive a novel quasi-local conservation law of the anisotropic Heisenb
erg model\, by means of which we rigorously estimate the spin Drude weight
(the ballistic transport coefficient) in the easy-plane regime.\n\n//indi
co.ictp.it/event/a12316/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12316/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Noise-induced metastabil
ity in biochemical networks"
DTSTART;VALUE=DATE-TIME:20121120T150000Z
DTEND;VALUE=DATE-TIME:20121120T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12322@ictp.it
DESCRIPTION:With recent advances in experimental techniques\, it is becomi
ng increasingly clear that the dynamics of cellular biochemical reactions
are subject to a great deal of noise. This poses a significant challenge
to our understanding of such systems\, as it has been known for some time
that the effects of noise may lead to substantial differences in the macro
scopic behaviour. Here\, we report analytical progress on this problem ma
de by studying a simple class of reaction networks whose dynamical behavio
ur is radically affected by intrinsic stochasticity in finite volume cells
. In particular\, we show how networks of this type give rise to a separa
tion of timescales between fast almost-deterministic oscillations and slow
stochastic metastability. Our class includes the influential Togashi-Kan
eko (TK) reaction scheme\, which has been found to undergo a noise-induced
dynamical transition via numerical simulations. Despite the importance o
f their work\, a satisfactory analytic treatment of this effect has not be
en achieved in over a decade. Here we provide such a treatment as an appl
ication of our theory.\n\n//indico.ictp.it/event/a12322/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a12322/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Thermodynamics and
the quantum stress-energy and spin tensor"\n
DTSTART;VALUE=DATE-TIME:20121121T150000Z
DTEND;VALUE=DATE-TIME:20121121T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12323@ictp.it
DESCRIPTION:In this seminar we show that thermodynamics is sensitive to th
e existence of a fundamental spin tensor\, predicted by extensions of gene
ral relativity. In general\, thermodynamics is not invariant by a change
of the stress-energy tensor of a fundamental quantum field with a divergen
ce transformation leaving the total energy\, momentum and angular momentum
unchanged. Among the quantities which are changed by such a transformatio
n\, there are densities at equilibrium with rotation and non-equilibrium o
nes like transport coefficients and total entropy. Therefore\, at least i
n principle\, it could be possible to probe the existence of a spin tensor
with a thermodynamics experiment.\n\n//indico.ictp.it/event/a12323/
LOCATION:SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a12323/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Spin liquid
s in quantum antiferromagnetic models on two dimensional frustrated lattic
es"\n\n
DTSTART;VALUE=DATE-TIME:20121122T103000Z
DTEND;VALUE=DATE-TIME:20121122T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12324@ictp.it
DESCRIPTION:For many decades physicists have been searching for "hot'' eno
ugh playgrounds that can melt magnetic freezing even at extremely low temp
eratures\, purely due to strong quantum fluctuations. The resulting quant
um paramagnetic phases of matter called spin liquids\, do not spontaneousl
y break any symmetries\, possess quantum and topological orders\, and cons
equently fall outside the paradigm of traditional condensed matter theory
based on the Landau's Fermi liquid theory and Landau's theory of phase tra
nsitions. Remarkably enough\, the "deceptively'' simple spin-1/2 Heisenbe
rg antiferromagnetic model\, when put on the most frustrated lattice\, the
"kagome'' lattice\, has been shown\, both experimentally and theoreticall
y to host such an exotic state. I will present my research work dealing w
ith the precise identification of this state\, which is currently being de
bated very intensely. I will show\, within fermionic slave particle approa
ches\, that a certain "marginally'' stable spin liquid with a U(1) low ene
rgy gauge structure (so-called Dirac spin liquid) is remarkably robust to
all known perturbations towards stable Z2 spin liquids and Valence-bond cr
ystals\, despite having strongly interacting gapless fermionic excitations
down to zero energy. Finally\, using state-of-the-art numerical techniqu
es such as the application of Lanczos steps on variational wave functions
combined with Green's function Monte Carlo technique\, I will show that su
ch an exotic algebraic spin liquid can in fact exist as a real physical sp
in liquid ground state.\n\nPUBLICATIONS:\n\n1.) Phys. Rev. B 83\, 100404 (
2011) - Y. Iqbal\, F. Becca\, and D. Poilblanc.\n2.) Phys. Rev. B 84\, 020
407 (2011) (Editor's suggestion) - Y. Iqbal\, F. Becca\, and D. Poilblanc.
\n3.) New J. Phys 14\, (in press) (2012)\; arXiv: 1203.3421 - Y. Iqbal\, F
. Becca\, and D. Poilblanc.\n4.) arXiv: 1209.1858 [cond.mat] (2012) - Y. I
qbal\, F. Becca\, S. Sorella\, and D. Poilblanc.\n\n//indico.ictp.it/event
/a12324/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12324/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: "Infinite family of
second-law-like inequalities"
DTSTART;VALUE=DATE-TIME:20121127T103000Z
DTEND;VALUE=DATE-TIME:20121127T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12327@ictp.it
DESCRIPTION:The probability distribution function for an out of equilibriu
m system may sometimes be approximated by a physically motivated "trial" d
istribution. A particularly interesting case is when a driven system (e.g.
\, active matter) is approximated by a thermodynamic one. We show here tha
t every set of trial distributions yields an inequality playing the role o
f a generalization of the second law. This suggests a variational procedur
e that may be implemented numerically and even experimentally to approxima
te the distribution function in terms of effective interactions. The fluct
uation relation behind this inequality\, -a natural and practical extensio
n of the Hatano-Sasa theorem-\, does not rely on the a priori knowledge of
the stationary probability distribution.\n\n//indico.ictp.it/event/a12327
/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12327/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical physics seminar: " An alternative roa
d to Bethe Ansatz equations"
DTSTART;VALUE=DATE-TIME:20121128T100000Z
DTEND;VALUE=DATE-TIME:20121128T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12328@ictp.it
DESCRIPTION:In the last few years\, a link between Bethe Ansatz equations
for conformal field theories and spectral functions of simple ordinary dif
ferential operators has emerged. Assuming no prior knowledge of this topi
c\, this talk will review the key facts about this surprising link and dis
cuss recent important findings concerning its off-critical generalisation.
\n\n//indico.ictp.it/event/a12328/
LOCATION:SISSA\, Santorio Building\, Room 138 (1st Floor)
URL://indico.ictp.it/event/a12328/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "The phase d
iagram of one-dimensional disordered bosons at ultralow temperature"
DTSTART;VALUE=DATE-TIME:20121129T103000Z
DTEND;VALUE=DATE-TIME:20121129T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12329@ictp.it
DESCRIPTION:The interplay of disorder and interactions can have a large im
pact on the properties of quantum systems. It is well known that\, wherea
s non-interacting particles can be localized by the destructive interferen
ce in a disordered potential\, a weak repulsive interaction tends to estab
lish coherence between single-particle localized states\, thus weakening o
r destroying such localization. The interplay of disorder and strong inte
ractions is instead still a challenging problem. One paradigmatic problem
is that of low-temperature bosonic particles confined to a one-dimensiona
l disordered environment\, which\, in addition to the standard superfluid
and Mott phases\, has been predicted to show a peculiar gapless insulating
phase\, the Bose glass [1\,2]\, that is still proving to be elusive in ex
periments. We investigate the behavior of a bosonic quantum gas close to
T=0 confined in a one-dimensional quasi-periodic lattice\, where interacti
ons and disorder can be independently tuned. By studying its momentum dis
tribution\, mobility and excitation spectrum features\, we trace out a pha
se diagram showing a coherent phase surrounded by a gapless insulator. Th
e latter has a bosonic character at low interactions\, and a fermionic one
at large interactions\, consistently with the expectations for the presen
ce of a Bose glass phase. Our results confirm long-standing theoretical p
redictions and indicate the way to study still open questions in 1D bosons
and analogous disordered problems in higher dimensions and/or with fermio
ns.\n\n[1] D. S. Fisher\, Phys.Rev. B 40\, 546 (1989).\n[2] T. Giamarchi\,
Phys. Rev. A 78\, 023628 (2008).\n\n//indico.ictp.it/event/a12329/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12329/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: " Relaxation after a
sudden quench: Insights from exactly solvable models"\n
DTSTART;VALUE=DATE-TIME:20121204T100000Z
DTEND;VALUE=DATE-TIME:20121204T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12331@ictp.it
DESCRIPTION:I consider the time evolution of observables and reduced densi
ty matrices after a sudden\nquench of a Hamiltonian parameter in one dimen
sional systems. I discuss the issue of\nrelaxation and show quite generall
y that if subsystems relax and can be described in terms\nof a statistical
ensemble\, dynamical correlations are described by the same ensemble as w
ell.\nThen I consider quenches in the transverse field Ising chain\, where
many exact results have\nbeen recently obtained. I focus on the approach
to the stationary state (which\, in the specific\ncase\, is a generalized
Gibbs ensemble) and discuss the relation between time averages and\nlate t
ime dynamics.\n\n//indico.ictp.it/event/a12331/
LOCATION:SISSA\, Santorio Building\, Room 134 (1st Floor)
URL://indico.ictp.it/event/a12331/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Quantum que
nch in p+ip superfluids: Non-equilibrium topological gapless state"\n\n
DTSTART;VALUE=DATE-TIME:20121206T103000Z
DTEND;VALUE=DATE-TIME:20121206T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12330@ictp.it
DESCRIPTION:Ground state "topological protection" has emerged as a main th
eme in quantum condensed matter physics. A key question is the robustness
of physical properties including topological quantum numbers to perturbat
ions such as disorder or non-equilibrium driving.\nIn this work we investi
gate the dynamics of a p+ip superfluid following a zero temperature quantu
m quench. The model describes a 2D topological superconductor with a non-t
rivial (trivial) BCS (BEC) phase. We work with the full interacting BCS Ha
miltonian\, which we solve exactly in the thermodynamic limit using classi
cal integrability. The non-equilibrium phase diagram is obtained for gener
ic quenches. A large region of the phase diagram describes strong to weak
-pairing quenches wherein the order parameter vanishes in the long-time li
mit\, due to pair fluctuations. Despite this\, we find that the topologic
al winding number survives for quenches in this regime\, leading to the pr
ediction of a "gapless topological" state.\nWe discuss potential realizati
ons\, including a proximity effect quench on the surface of 3D topological
insulator.\n\n//indico.ictp.it/event/a12330/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12330/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Heat fluctuations i
n a quenched ferromagnet"
DTSTART;VALUE=DATE-TIME:20121207T100000Z
DTEND;VALUE=DATE-TIME:20121207T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12335@ictp.it
DESCRIPTION:The off-equilibrium probability distribution of the heat excha
nged by a ferromagnet in a time interval after a quench below the critica
l point is calculated analytically in the large-N limit. Here N is the nu
mber of components of the vectorial order parameter. The distribution sho
ws a singular behavior with a critical threshold below which a macroscopic
fraction of heat is released by the k=0 Fourier mode of the order paramet
er. The mathematical structure producing this phenomenon is the same resp
onsible of the order parameter condensation in the equilibrium low tempera
ture phase. The heat exchanged by the individual Fourier modes follows a
non trivial pattern\, with the unstable modes at small wave vectors warmin
g up the modes around a characteristic finite wave vector k_M. Two interna
l temperatures\, associated to the k=0 and k=k_M modes\, rule the heat cur
rents through a fluctuation relation similar to the one for stationary sys
tems in contact with two thermal reservoirs.\n\n//indico.ictp.it/event/a12
335/
LOCATION:SISSA\, Santorio Building\, Room 138 (1st Floor)
URL://indico.ictp.it/event/a12335/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Entanglement\, nonl
ocality\, signaling and cloning"
DTSTART;VALUE=DATE-TIME:20121211T103000Z
DTEND;VALUE=DATE-TIME:20121211T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12337@ictp.it
DESCRIPTION:Quantum entanglement between two far-away constituents of a co
mposite system\, when considered in conjunction with a measurement process
on one of them\, raises some serious problems due to the instantaneous re
duction of the state of the other. In some sense one could state that an a
ction performed in a given space time region can affect immediately a syst
em which is space like separated from it.\nIt is not surprising that this
peculiar aspect of quantum mechanics has given rise\, from the seventies u
p to now\, to many proposals to achieve superluminal communication betwee
n distant observers. Almost all such proposals have been shown to be wrong
on the basis of general theorems by P. Eberhard and by our group.\nHowev
er\, in 1982\, a quite tricky new proposal has been put forward by N. Herb
ert whose refusal required the derivation of a new theorem\, which has pla
yed and plays an important role for quantum computation and quantum commun
ication: the no-cloning theorem.\nThe seminar intends to briefly review th
e debate about this interesting issue which involves many subtle aspects o
f quantum mechanics and to make clear the events which led to the derivati
on of the no-cloning theorem.\nFinally\, attention will be paid to the gen
eral problem of the compatibility of the reduction process "at-a-distance"
and relativistic requirements\, specifically in the light of the recent p
roposals of relativistic generalizations of "collapse theories".\n\n//ind
ico.ictp.it/event/a12337/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12337/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Condensatio
n vs lasing and superfluidity of coupled light-matter systems"\n
DTSTART;VALUE=DATE-TIME:20121213T103000Z
DTEND;VALUE=DATE-TIME:20121213T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12336@ictp.it
DESCRIPTION:The great experimental progress in realising and studying pola
riton condensates has made it possible to now study experimentally a numbe
r of fundamental questions about the relation between lasing\, condensatio
n\, coherence and superfluidity. In my talk\, I will discuss the conseque
nces of finite particle lifetime on several of these questions. I will di
scuss the relation between lasing as described by the Maxwell-Bloch equati
ons and polariton condensation\, and discuss the consequences of this for
both polariton and photon condensation [1]. I will also address aspects o
f superfluidity [2]\, pattern formation [3] and coherence[3]\, and discuss
how these are affected by the finite lifetime of polaritons.\n\n[1] J. K
eeling\, M. H. Szymanska\, and P. B. Littlewood p. 293 of Optical generati
on and control of quantum coherence in semiconductor\n nanostructure
s (2010) Eds. G. Slavcheva and P. Roussignol\n[2] J. Keeling\, Phys. Rev.
Lett. 107 080402 (2011) \n[3] J. Keeling and N. G. Berloff Phys. Rev. Lett
. 100 250401 (2008)\n[4] G. Roumpos et al\, Proc. Natl. Acad. Sci\, 109 64
67(2012)\n\n//indico.ictp.it/event/a12336/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12336/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Quantum quench in t
he sinh-Gordon model"
DTSTART;VALUE=DATE-TIME:20121214T130000Z
DTEND;VALUE=DATE-TIME:20121214T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12340@ictp.it
DESCRIPTION:We study a quantum quench in the sinh-Gordon model starting fr
om a large initial mass and zero initial interaction and quenching to any
value of the mass and interaction. Such a quench can be approximated by a
Dirichlet initial state which\, being an example of a so-called "squeezed
vacuum" state\, can be evolved in time using earlier work [1]. However the
use of an idealized Dirichlet state leads to UV divergences and it turns
out that the UV behaviour of the actual initial state is relevant to the c
alculation of physical observables. Based on a general method to expand th
e initial state on the post-quench energy eigenstates [2]\, we verify that
the actual state is of the squeezed vacuum form and derive the correct UV
modification that has to be applied on the Dirichlet state in order to de
scribe a quantum quench. We compare with different UV regularization schem
es that have been proposed and comment on the applicability of renormaliza
tion group tools in quantum-quench problems.\n\n[1] D. Fioretto\, G. Mussa
rdo\, Quantum Quenches in Integrable Field Theories\, New J.Phys.12 055015
\, 2010.\n[2] S. Sotiriadis\, D. Fioretto\, G. Mussardo\, Zamolodchikov-Fa
ddeev Algebra and Quantum Quenches in Integrable Field Theories\, J. Stat.
Mech. (2012) P02017\, 2012.\n\n//indico.ictp.it/event/a12340/
LOCATION:SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a12340/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Ultracold atoms wit
h tunable interactions in confined geometry"
DTSTART;VALUE=DATE-TIME:20121218T100000Z
DTEND;VALUE=DATE-TIME:20121218T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12345@ictp.it
DESCRIPTION:Ensembles of ultracold atoms and molecules loaded into lattice
potentials are ideally suited to perform model studies of condensed matte
r systems. In fact\, the hope is that ultracold atoms and molecules will s
ome day find use as “quantum simulators” to simulate the properties of
a complex many-body system in a fully quantum way. I will present a seri
es of experiments with ultracold atoms in lattices for we tune the interac
tion properties. For example\, we produce a meta-stable Mott state pinned
by attractive interactions. In one-dimensional geometry\, we investigate t
he transition to a pseudo anti-ferromagnetic state. I will outline our att
empts to go beyond local interactions by preparing dipolar quantum gases o
f heteronuclear molecules.\n\n//indico.ictp.it/event/a12345/
LOCATION:SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a12345/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Topological blockad
e and braiding of non-Abelian anyons via interactions"\n
DTSTART;VALUE=DATE-TIME:20121219T103000Z
DTEND;VALUE=DATE-TIME:20121219T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12344@ictp.it
DESCRIPTION:The fractionally charged quasiparticles appearing in the 5/2 f
ractional quantum Hall plateau are predicted to have an extra non-local de
gree of freedom\, known as topological charge. I will show how this topol
ogical charge can block the tunnelling of these particles\, and how such '
topological blockade' can be used to readout their topological charge. Mo
reover I will examine more in general the role that interactions between n
on-Abelian anyons play in topological quantum computation and how these in
teractions can be exploited to implement braiding operators.\n\n//indico.i
ctp.it/event/a12344/
LOCATION:SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a12344/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "The Yang-Ba
xter equation and diffraction"\n
DTSTART;VALUE=DATE-TIME:20121220T103000Z
DTEND;VALUE=DATE-TIME:20121220T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a12346@ictp.it
DESCRIPTION:Integrable interactions are synonymous with non-diffractive sc
attering\, meaning that the set of incoming momenta for any scattering eve
nt coincides with the set of outgoing momenta. A system is integrable if
the two particle scattering matrix obeys a particular relation known as th
e Yang-Baxter equation. Nonintegrable interactions correspond to diffract
ive scattering\, where the set of outgoing momenta may take on all values
consistent with energy and momentum conservation. Such processes play a vi
tal role in the kinetics of one dimensional gases\, where binary collision
s are unable to alter the distribution function.\nIn this talk I'll discus
s how diffractive scattering arises when the Yang-Baxter equation is viola
ted\, and show how to calculate the diffraction amplitude when this violat
ion is small.\n\n//indico.ictp.it/event/a12346/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a12346/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Corner contribution
to percolation cluster numbers"\n
DTSTART;VALUE=DATE-TIME:20130115T103000Z
DTEND;VALUE=DATE-TIME:20130115T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a134@ictp.it
DESCRIPTION:We study the number of clusters in 2d critical percolation\, N
Γ \, which intersect a given subset of bonds\, Γ. In the simplest case\,
when Γ is a simple closed curve\, NΓ is related to the entanglement ent
ropy of the critical diluted quantum Ising model\, in which Γ represents
the boundary between the subsystem and the environment. Due to corners in
Γ there are universal logarithmic corrections to NΓ \, which are calcula
ted in the continuum limit through conformal invariance making use of the
Cardy-Peschel formula. The exact formulae are confirmed by large scale Mon
te Carlo simulations. These results are extended to anisotropic percolatio
n where they confirm a result of discrete holomorphicity.\n\nI. A. Kovács
\, F. Iglói and J. Cardy\, Phys. Rev. B 86\, 214203 (2012)\, arXiv:1210.4
671\n\n//indico.ictp.it/event/a134/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a134/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlation: "Graphene wit
h vacancies: Density of states\, transport\, multifractality"\n\n
DTSTART;VALUE=DATE-TIME:20130117T103000Z
DTEND;VALUE=DATE-TIME:20130117T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a137@ictp.it
DESCRIPTION:A single vacancy in an otherwise clean flake of graphene intro
duces a topological defect. It punches a new state at zero energy into th
e Dirac cone (zero mode). A finite concentration of such vacancies produce
s a narrow impurity band that determines the low energy/frequency response
of the flake. A peculiarity of this band is that its properties are very
sensitive to details of the impurity placings:\nAll impurities in one subl
attice imply a density of states (DoS) vanishing in the zero energy limit\
, while impurities distributed equally over both sublattices (compensated)
exhibit a diverging DoS.\n\nWe present a numerical study focussing mainly
on the DoS at very low energies. We resolve the Dyson-singularity with co
mpensated disorder and investigate the amplitude statistics (multifractali
ty) of the associated wavefunctions. Finally\, we present transport calcul
ations addressing the possibility of Anderson-localization on percolation
clusters preempting the classical localization transition.\n\n//indico.ict
p.it/event/a137/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a137/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Dynamics of highly
excited many-body states -- diffusion and localization at finite entropy"
DTSTART;VALUE=DATE-TIME:20130122T100000Z
DTEND;VALUE=DATE-TIME:20130122T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1318@ictp.it
DESCRIPTION:I will survey some recent ideas and results on transport and d
ynamics of excited interacting systems with and without disorder. While i
n some cases existence of macroscopic diffusion can be verified\, in other
cases\, e.g. in the presence of localization on microscopic scales\, emer
gence of diffusion may be thwarted. The conditions for existence of such
many body localized phases appear to be generic\, provided the disorder is
strong and interactions are sufficiently short ranged.\n\n//indico.ictp.i
t/event/a1318/
LOCATION:SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a1318/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Overview of 1D tens
or networks and their application to quantum phase transitions"\n
DTSTART;VALUE=DATE-TIME:20130129T103000Z
DTEND;VALUE=DATE-TIME:20130129T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1323@ictp.it
DESCRIPTION:I will introduce Tensor Network states and explain in this con
text two strategies for extracting universal quantities at conformal invar
iant fixed point of spin chains. One of them the scaling approach is bette
r suited to simple tensor networks such as matrix product states and tree
tensor networks. More sophisticated tensor networks (such as the MERA) all
ow to directly extract universal properties from the tensors of the networ
k.\nI will present results obtained through both approaches.\n\n//indico.i
ctp.it/event/a1323/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1323/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Informal seminar on Statistical Physics : "Entrop
y barriers and glass-like behaviour in \nmartensitic models without extrin
sic disorder"\n
DTSTART;VALUE=DATE-TIME:20130204T140000Z
DTEND;VALUE=DATE-TIME:20130204T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1330@ictp.it
DESCRIPTION:A 2D model of three-valued discrete-strain pseudospins S (r)=0
\, +1\,-1 is studied in Monte Carlo simulations\, under systematic tempera
ture quenches\, without extrinsic disorder [1]. The reduced model is from
Landau minima of a continuum-strain free energy of the square-rectangle m
artensitic transition. The pseudospins interact via a power-law anisotropi
c potential obtained from the St Venant Compatibility constraint. The sam
e procedure yields pseudospin models for other 2D and 3D transitions [2].
After a temperature quench\, dilute martensitic seeds in an austenite bac
kground\, induce sequential domain-wall phases of a 'vapour' of a martens
ite droplet in austenite\; a 'liquid' of disordered martensite domain wal
ls\; and a ‘crystal’ of oriented-wall twins. The evolution is tracked
through Temperature-Time –Transformation (TTT) curves\, with time scale
s for conversion to martensite t_m (T)\; and Compatibility-driven domain-
wall orientation\, t_C (T). Depending on elastic constants\, t_m (T) can
either be thermally activated and slow\, as in 'isothermal' martensites\;
or non-activated and explosive\, as in 'athermal' martensites below a mar
tensite start temperature ~ T_1. For quenching to above such a temperatur
e\, we find (generically) a delay tail\, that rises towards a temperature
T=T_4 > T_1. This is identified with the puzzling delay tail in t_m (T)
found by Kakeshita [3]. The mean time shows glass-like Vogel-Fulcher beh
aviour\, t_m ~ exp [ 1/( T_4 - T)]\, and distributions are log-normal [1].
The times are insensitive to the Hamiltonian energy scale E_0\, and are
attributed to entropy barriers that vanish/ diverge at T_1 and T_4. The c
onversion delays are from searches in Fourier space on constant-energy sur
faces\, for rare energy-lowering pathways. The 'vapour' phase structure-f
actor peak has to find pathways to distort and roll into a small anisotrop
ic 'golf hole'\; to be then guided by a 'funnel' into a 'liquid' phase\;
and finally symmetry-broken\, to a 'crystal' phase. A time- dependent ef
fective temperature re-equilibrates to the bath temperature. The entropic
golf-hole\, and energetic funnel\, are concepts from protein folding [4].
\n\n[1] N. Shankaraiah\, K.P.N. Murthy\, T. Lookman and S.R .Shenoy\, Euro
phys. Lett. 92\, 36002 (2010)\; Phys. Rev. B 84\, 064119 (2011) \; and unp
ublished.\n[2] S.R. Shenoy\, T. Lookman and A. Saxena\, Phys. Rev. B 82\,
(2010).\n[3] T. Kakeshita\, T. Fukuda and T. Saburi\, Scr. Mater. 34\, 1
(1996)\; L. Mueller\, U. Klemradt and T.R. Finlayson\, Mater. Sci. Eng. A\
, 438\, 122 (2006).\n[4] P.G. Wolynes\, et al. Science 267\, 1619 (1995)\;
D.J. Bicout and A. Szabo\, Protein Science 9\, 452 (2000)\; N. Nakagawa\,
Phys. Rev. Lett.98\, 128104 (2007).\n\n//indico.ictp.it/event/a1330/
LOCATION:SISSA\, Santorio Building\, Room 5 (ground floor)
URL://indico.ictp.it/event/a1330/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISA Statistical Physics seminar: "Entanglement spectra
: A novel spectroscopic tool to investigate \nquantum many body wave func
tions"\n
DTSTART;VALUE=DATE-TIME:20130205T103000Z
DTEND;VALUE=DATE-TIME:20130205T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1329@ictp.it
DESCRIPTION:The entanglement spectrum\, ie the logarithm of the eigenvalue
s of reduced density matrices of quantum many body wave functions\, has be
en the focus of a rapidly expanding research endeavor recently. Initially
introduced by Li & Haldane in the context of the fractional quantum Hall
effect\, its usefulness has been shown to extend to many more fields\, suc
h as topological insulators\, fractional Chern insulators\,\nspin liquids\
, continuous symmetry breaking states\, etc.\nAfter a general introduction
to the field we review some of our own contributions to the field\, in pa
rticular the perturbative structure of the entanglement spectrum in gapped
phases\, the entanglement spectrum across the Mott-insulator transition i
n the Bose-Hubbard model\, and the relation of the entanglement spectrum o
f (1+1) dimensional quantum critical systems to the operator content of th
eir underlying CFT.\n\n//indico.ictp.it/event/a1329/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1329/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Bose-Einste
in condensed gas with equal Rashba and Dresselhaus spin-orbit coupling"\n
DTSTART;VALUE=DATE-TIME:20130207T103000Z
DTEND;VALUE=DATE-TIME:20130207T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1328@ictp.it
DESCRIPTION:We consider a spin-orbit (SO) coupled configuration of spin-1/
2 interacting bosons with equal Rashba and Dresselhaus couplings. The phas
e diagram of the system at T=0 is discussed with special emphasis on the r
ole of the interaction\, treated in the mean-field approximation. For a cr
itical value of the density and of the Raman coupling we predict the occur
rence of a characteristic tricritical point separating the stripe\, the sp
in polarized and the zero momentum states of the Bose gas. The role of the
breaking of spin symmetry in the interaction Hamiltonian\, as well as the
compressibility and the spin polarizability of the system are discussed.\
nBy using the hydrodynamic formalism we identify the excitation spectrum a
t zero temperature. The propagation of phonons is strongly affected by the
SO coupling and the velocity of sound vanishes when one approaches the se
cond order phase transition between the spin polarized and the zero moment
um quantum phases. We also point out the emergence of a roton minimum in t
he excitation spectrum for small values of the Raman coupling\, when one a
pproaches the transition to the stripe phase.\n\n//indico.ictp.it/event/a1
328/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1328/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Clifford algebra fo
r complex problems"
DTSTART;VALUE=DATE-TIME:20130212T100000Z
DTEND;VALUE=DATE-TIME:20130212T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1334@ictp.it
DESCRIPTION:In this talk I will present some complex\, NP-complete problem
s\, formulated in Clifford (spinor) Algebra. I will show that typically th
ese problems require only a polynomial number of Clifford multiplications.
I will then treat briefly the computational complexity of Clifford operat
ions.\nSubsequently I will present some results for Clifford algebras in a
rbitrary dimension that allow to better tackle the initial formulation of
the complex problems.\n\n//indico.ictp.it/event/a1334/
LOCATION:SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a1334/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Critical an
d thermodynamic properties of lattice bosons"\n
DTSTART;VALUE=DATE-TIME:20130214T103000Z
DTEND;VALUE=DATE-TIME:20130214T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1337@ictp.it
DESCRIPTION:We investigate\, using series expansion techniques\, the effec
ts of higher-body local interactions in softcore lattice bosons and find t
hat there is a systematic procedure to exactly renormalize the two-body in
teractions at every perturbative order\; this is found to be applicable to
quantum critical as well as ground state properties within the Mott insul
ating lobe. Preliminary work on finite temperature effects in interacting
hardcore bosons (XXZ-type spin models) will be briefly mentioned.\n\n//in
dico.ictp.it/event/a1337/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1337/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "A scalable algorith
m to explore the Gibbs energy landscape of genome-scale metabolic networks
"
DTSTART;VALUE=DATE-TIME:20130219T103000Z
DTEND;VALUE=DATE-TIME:20130219T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1342@ictp.it
DESCRIPTION:The integration of various types of genomic data into predicti
ve models of biological networks is one of the main challenges currently f
aced by computational biology. Constraint-based models in particular play
a key role in the attempt to obtain a quantitative understanding of cellul
ar metabolism at genome scale. In essence\, their goal is to frame the met
abolic capabilities of an organism based on minimal assumptions that descr
ibe the steady states of the underlying reaction network via suitable stoi
chiometric constraints\, specifically mass balance and energy balance (i.e
. thermodynamic feasibility). The implementation of these requirements to
generate viable configurations of reaction fluxes and/or to test given flu
x profiles for thermodynamic feasibility can however prove to be computati
onally intensive. We propose here a fast and scalable stoichiometry-based
method to explore the Gibbs energy landscape of a biochemical network at s
teady state. The method is applied to the problem of reconstructing the Gi
bbs energy landscape underlying metabolic activity in the human red blood
cell\, and to that of identifying and removing thermodynamically infeasibl
e reaction cycles in the Escherichia coli metabolic network (iAF1260). In
the former case\, we produce consistent predictions for chemical potential
s (or log-concentrations) of intracellular metabolites\; in the latter\, w
e identify a restricted set of loops (23 in total) in the periplasmic and
cytoplasmic core as the origin of thermodynamic infeasibility in a large s
ample of flux configurations generated randomly and compatibly with the pr
ior information available on reaction reversibility.\n\n//indico.ictp.it/e
vent/a1342/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1342/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "The iron su
perconductors: Mott physics hides behind the orbitals"\n\n
DTSTART;VALUE=DATE-TIME:20130221T103000Z
DTEND;VALUE=DATE-TIME:20130221T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1344@ictp.it
DESCRIPTION:High-temperature superconductivity in the copper oxides is alm
ost universally associated with strong electron-electron correlations\, an
d the idea that superconductivity appear doping a Mott insulator. The iro
n-based superconductors do not seem to follow the same paradigm\, as the p
arent compounds are not insulating despite their magnetic ordering. Anoth
er key difference is that\, while the cuprates can be described with a sin
gle valence band\, in the iron materials it appears necessary to consider
all five iron d-orbitals.\nRe-examining the experimental data for the effe
ctive mass\, we show that indeed the phase diagram of iron superconductors
is controlled by a Mott insulating state which would occur in a material
with a very large hole-doping\, while the parent compound is not close to
a Mott state despite the commensurate filling.\nThe reason for this behavi
or is a large Hund's coupling\, which decouples the orbitals turning the m
ulti orbital bandstructure into a collection of single-band Hubbard models
. This finding creates the strongest connection between cuprates and iron
superconductors. In both cases superconductivity appears around 20% doping
of a Mott insulator.\nAs a matter of fact the different single-band model
s have a different population (or doping) and therefore they have a differ
ent effective mass\, which simply corresponds to the distance from the Mot
t insulator. This also implies a strongly "orbital-selective" effective ma
ss\, which reconciles contrasting evidences of correlations in these mater
ials.\n\n//indico.ictp.it/event/a1344/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1344/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Finite volume matri
x elements in the sine-Gordon model"\n
DTSTART;VALUE=DATE-TIME:20130226T100000Z
DTEND;VALUE=DATE-TIME:20130226T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1346@ictp.it
DESCRIPTION:I will discuss finite volume matrix elements of local operator
s in integrable quantum field theories and present a conjecture relating f
inite and infinite volume form factors in the most general setting\, i.e.
including the case of form factors containing disconnected pieces in the p
resence of non-diagonal scattering. Specializing to the sine-Gordon model
\, finite volume multi-soliton form factors are compared to numerical data
coming from a numerical renormalization group calculation in the truncate
d conformal space. I find excellent agreement between the two approaches\
, thus verifying both bootstrap for multi-soliton form factors and the the
ory linking finite and infinite volume matrix elements. Evaluation of the
nontrivial multi-soliton form factors is achieved by a newly developed re
gularization scheme.\n\n//indico.ictp.it/event/a1346/
LOCATION:SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a1346/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Colloquium on Condensed Matter Physics: "The end
of the quantum spin ladder problem (almost)"
DTSTART;VALUE=DATE-TIME:20130227T153000Z
DTEND;VALUE=DATE-TIME:20130227T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1345@ictp.it
DESCRIPTION:For the past 25 years\, the Heisenberg S = 1/2 ladder remains
the most important model in quantum magnetism. It combines the essence of
quantum spin fluctuations with topological peculiarities of one dimension
. The vast amount of theoretical work performed over the years yielded a
comprehensive picture of spin correlations in this model\, and their evolu
tion in applied magnetic fields. Unfortunately\, good experimental realiz
ations and sufficiently accurate numerical results remained elusive. The
situation changed drastically in the past couple of years\, due to progres
s in material synthesis\, neutron scattering instrumentation and algorithm
development. We are now close to claiming that the spectral and thermody
namic properties of the quintessential J_rung-J_leg Heisenberg ladder mode
l are completely understood at the quantitative level. Particularly striki
ng are recent results on spin excitations in the strong-leg ladder materia
l DIMPY\, obtained in the gapped spin liquid [1-3] and gapless Tomonaga-Lu
ttinger spin liquid phases [3]. At the same time\, just slightly more com
plex ladder systems\, those showing disorder [4]\, geometric frustration [
5\,6] or a coupling to the crystal lattice [7]\, present new challenges th
at we are beginning to tackle.\n\nReferences\n1. T. Hong et al.\, P
hys. Rev. Lett. 105\, 137207 (2010).\n2. D. Schmidiger et al.\, Phy
s. Rev. B 84\,144421 (2011)\n3. D. Schmidiger et al.\, Phys. Rev. L
ett. 108\, 167201 (2012).\n4. T. Hong et al.\, Phys. Rev. B 81\, [R
apid] 060410 (2010).\n5. V. O. Garlea\, et al.\, Phys. Rev. Lett. 1
00\, 037206 (2008).\n6. V. O. Garlea\, et al.\, Phys. Rev. B 79\, [
Rapid] 060404 (2009).\n7. F. Schrettle\, et al.\, Phys. Rev. B [Rap
id]-in press\, arXiv:1203.3127v1.\n\n//indico.ictp.it/event/a1345/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1345/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:\n"Resonant B
ose-Fermi mixtures: A T-matrix and Quantum Monte Carlo study"\n
DTSTART;VALUE=DATE-TIME:20130228T103000Z
DTEND;VALUE=DATE-TIME:20130228T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1350@ictp.it
DESCRIPTION:We develop the theoretical study of a novel physical system\,
in the context of ultracold gases. We investigate the physical behavior o
f a resonant Bose-Fermi mixture\, namely\, an ultracold gas made of both b
osons and fermions\, with a strong attractive interaction between these tw
o components.\nWe study homogeneous density and mass imbalanced mixtures f
rom weak- to strong- coupling limit\, comparing the results obtained with
two different theoretical approaches\, a many-body diagrammatic approach (
the T- matrix approximation) and Quantum Monte Carlo method.\nBy using man
y-body diagrammatic methods we first obtain the finite-temperature phase d
iagram and the thermodynamic properties of the system. We observe the pre
sence of a quantum phase transition from the condensed (superfluid) to the
normal (molecular) phase. Developing the zero-temperature limit of the s
ame Green’s function formalism we study the effect of density and mass i
mbalances for the Bose-Fermi mixture. By using the corresponding retarded
propagators we calculate the spectral weight functions and the dispersion
s of bosons and fermions.\nWe apply for the first time the Quantum Monte C
arlo method with Fixed-Node approximation to investigate resonant Bose-Fer
mi mixture\, from weak to strong boson-fermion attraction. Two different
nodal surfaces are used as trial wave functions in the two regimes. We ob
tain the equation of state of a density imbalanced mixture and we observe
the presence of the quantum phase transition through the crossing of the e
nergies\, calculated with their respective trial wave functions. A phase
diagram in the coupling and boson-fermion concentration variables is deriv
ed and the occurrence of phase separation is discussed. We compare Quantu
m Monte Carlo results to T-matrix calculations\, finding an interesting ag
reement between the results.\n\n//indico.ictp.it/event/a1350/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1350/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter seminar: "Structures of metallic
nanoparticles and nanoalloys"
DTSTART;VALUE=DATE-TIME:20130228T143000Z
DTEND;VALUE=DATE-TIME:20130228T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1351@ictp.it
DESCRIPTION:The structures of metallic nanoparticles are searched for by a
computational methodology combining global optimization searches within a
n atomistic model and density-functional local relaxation. Different syste
ms are considered\, from single-metal nanoparticles adsorbed on magnesium
oxide\, to free and supported nanoalloys.\nMetallic nanoparticles adsorbed
on MgO are of great interest for applications in catalysis. Here we show
that a variety of different morphologies can be obtained depending on the
magnitude of the lattice mismatch and on the interaction strength with the
substrate. We consider Au\, Ag and Ni clusters on MgO(100) and compare ou
r results with the experimental findings.\nNanoalloys with core-shell arra
ngement are of special interest in applications\, such as in optics\, cata
lysis\, magnetism and biomedicine. Despite this wide interest\, the physic
al factors stabilizing the structures of these nanoparticles are still unc
lear to a great extent\, especially for what concerns the relationship bet
ween geometric structure and chemical ordering.\nHere global-optimization
searches are performed in order to determine the most stable chemical orde
ring patterns corresponding to the most important geometric structures\, f
or a series of weakly miscible systems\, including AgCu\, AgNi\, AgCo andC
AuCo. Our calculations show that\na) the overall geometric structure of t
he nanoalloy and the shape and placement of its inner core are strictly co
rrelated\; b) centered cores can be obtained in icosahedral nanoparticles
but not in crystalline or decahedral ones\, in which asymmetric quasi-Janu
s morphologies form\;\nc) in icosahedral nanoparticles\, when the core exc
eeds a critical size\, a new type of morphological instability develops\,
making the core asymmetric and extending it towards the nanoparticle\; d)
multi-center patterns can be obtained in large polyicosahedral nanoalloys.
\nAnalogies and differences between the instability of the core in icosahe
dral nanoalloys and the Stranski-Krastanov instability occurring in thin-f
ilm growth are discussed. All these issues are crucial for designing strat
egies to achieve effective coatings of the cores.\n\n//indico.ictp.it/even
t/a1351/
LOCATION:SISSA\, Santorio Building\, Room 131 (1st floor)
URL://indico.ictp.it/event/a1351/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Computing with anyo
ns"
DTSTART;VALUE=DATE-TIME:20130305T103000Z
DTEND;VALUE=DATE-TIME:20130305T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1352@ictp.it
DESCRIPTION:2D physical systems with degenerate grounds states and excited
particle states obeying exotic statistics ('anyons') provide a surprising
ly effective and aesthetically appealing arena for performing quantum\ncom
putation. Topological quantum computation is a rapidly expanding research
area focused on the physical realisation of a quantum computer that is i
ntrinsically fault-tolerant and decoherence free. The theoretical backgro
und needed for dealing with 'topological' systems and materials will be pr
esented in an pedagogical way.\n\n//indico.ictp.it/event/a1352/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1352/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Utility and
detection of work fluctuation theorems in many-body physics"\n\n
DTSTART;VALUE=DATE-TIME:20130307T103000Z
DTEND;VALUE=DATE-TIME:20130307T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1356@ictp.it
DESCRIPTION:The statistics of work done and associated fluctuation theorem
s give a novel thermodynamic interpretation of dynamics in quantum systems
. Here\, we apply the fluctuation theorems to a sudden "quench" of a quant
um system of many interacting particles containing a critical point. The
results highlight that the fluctuations of a dynamical quantum system prov
ide a route understanding the emergence of thermodynamic irreversibility.
Furthermore I will show that the characteristic function of the work distr
ibution for a non-equilibrium process can be extracted from Ramsey interfe
rometry of a single probe qubit. Our scheme paves the way for the full cha
racterisation of non-equilibrium processes in a variety of complex quantum
systems\, ranging from atomic systems to NMR.\n\n//indico.ictp.it/event/a
1356/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1356/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Colloquium on Condensed Matter Physics: "Lithium
ions in spinel (LiMn_2O_4\, LiV_2O_4) nanowire"\n
DTSTART;VALUE=DATE-TIME:20130308T103000Z
DTEND;VALUE=DATE-TIME:20130308T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1355@ictp.it
DESCRIPTION:Lithium ion transport attracts much interest because it is fun
damental process at lithium ion battery electrodes\, particularly at nanow
ire electrodes. To study irreversible transport process at charging–disc
harging process directly at atomic scale\, we developed an aberration corr
ected electron microscope which allows us to form an electron probe having
a diameter of sub-50pm. The spherical electron wave emitting from the ele
ctron probe scans the specimen surface was found for the first time to giv
e structure image of individual lithium ions. In electrodes of spinel stru
cture\, i.e.\, LiMn2O4\, dislocation of lithium ions from the tetrahedral
sites induces local structure change at octahedral sites\, which makes cha
rging-discharging cycle of ion transport irreversible#). Structure change
is discussed in relation to the current-voltage relation of a mode LIB. At
excess or deficient concentration of lithium ions\, spinel electrodes exh
ibited local disorder. To characterize local disorder\, we devised a new m
ethod which can allow us to find not only pair correlation but also higher
order correlation of the local disorder. \n#)This work is supported by CR
EST project\, “nanocycle at nano-in-macro interface”\n\n//indico.ictp.
it/event/a1355/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1355/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Equilibrium and non
equilibrium entanglement properties in Fermi gases/liquids"\n
DTSTART;VALUE=DATE-TIME:20130312T100000Z
DTEND;VALUE=DATE-TIME:20130312T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1360@ictp.it
DESCRIPTION:The equilibrium and nonequilibrium quantum evolution of extend
ed observables and entanglement properties are discussed in systems of Fer
mi gases/liquids of any dimension. In particular I focus on the entanglem
ent entropy of extended space regions at equilibrium and off-equilibrium d
uring the expansion after the drop of a trapping potential\, which general
ly shows multiplicative logarithmic corrections to the leading power-law b
ehaviors\, analogously to the logarithmic corrections to the area law in l
attice fermions.\n\n//indico.ictp.it/event/a1360/
LOCATION:SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a1360/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Pseudogap i
n ultracold Fermi gases: Theory\, experiments\, and QMC simulations"\n\n
DTSTART;VALUE=DATE-TIME:20130314T103000Z
DTEND;VALUE=DATE-TIME:20130314T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1364@ictp.it
DESCRIPTION:The origin of the pseudogap is widely debated for cuprate sup
erconductors. The main controversy concerns whether superconductivity and
the pseudogap phase are competing with each other or are manifestations of
the same phenomenon. In the latter case\, pairing fluctuations would exte
nd above the critical temperature (Tc) the effects of the pairing gap belo
w Tc [1].\nA contribution to settle this controversy can be obtained by ul
tracold fermions\, which are free of the structural complications of cupra
tes and where only pairing fluctuations are present above Tc. In these sys
tems\, the inter-particle attraction can be varied by Fano-Feshbach resona
nces as to amplify the effects of pairing fluctuations.\nIn this context\,
wave-vector resolved radio frequency spectroscopy data for an ultracold t
rapped Fermi gas are reported for several couplings at Tc\, and analyzed
by a pairing-fluctuation theory. We show that the non-Fermi-liquid behavio
r associated with the presence of a pseudogap coexists with a robust remna
nt Fermi surface over a wide coupling range\, which sets the boundary of t
he pseudogap phase [2\,3\,4].\nMoreover\, the properties of the pseudogap
phase obtained within the t-matrix approach are compared with the outcome
s of recent quantum Monte Carlo (QMC) ab initio simulations [5\,6].\nOnce
the pseudogap has been characterized in ultracold fermions\, we compare th
e temperature dependence of the spectral intensity suppression obtained wi
thin our theory with the one measured in cuprates by angular resolved phot
oemission spectroscopy (ARPES) [7].\n\nReferences\n\n[1] A. Perali\, P. Pi
eri\, G.C. Strinati\, and C. Castellani\, Phys. Rev. B 66\, 024510 (2002).
\n[2] J.P. Gaebler\, J.T. Stewart\, T.E. Drake\, D.S. Jin\, A. Perali\, P
. Pieri\, and G. C. Strinati\, Nature Physics 6\, 569 (2010).\n[3] A. Pera
li\, F. Palestini\, P. Pieri\, G.C. Strinati\, J. T. Stewart\, J. P. Gaeb
ler\, T. E. Drake\, and D. S. Jin\, Phys. Rev. Lett. 106\, 060402 (2011).
\n[4] F. Palestini\, A. Perali\, P. Pieri\, and G.C. Strinati\, Phys. Rev
. B 85\, 024517 (2012).\n[5] P. Magierski\, G. Wlazlowski and A. Bulgac\,
Phys. Rev. Lett. 107\, 145304 (2011).\n[6] G. Wlazlowski\, P. Magierski\,
J. E. Drut\, A. Bulgac\, and K. J. Roche\, Phys. Rev. Lett. 110\, 090401 (
2013).\n[7] T. Kondo\, Y. Hamaya\, A. D. Palczewski\, T. Takeuchi\, J. S.
Wen\, Z. J. Xu\, G. Gu\, J. Schmalian & A. Kaminski\, Nature Physics 7\, 2
1 (2011).\n\n//indico.ictp.it/event/a1364/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1364/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Non-equilibrium dyn
amics in isolated quantum systems"\n
DTSTART;VALUE=DATE-TIME:20130319T103000Z
DTEND;VALUE=DATE-TIME:20130319T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1373@ictp.it
DESCRIPTION:Quantum many-body physics has traditionally been dominated by
detailed investigations of equilibrium properties and low-energy excitatio
ns. In the last decade or so\, motivated by novel experimental possibiliti
es such as cold atoms\, the study of quantum matter far from equilibrium h
as emerged as an important and exciting new field.\nI will start with a se
lection of new questions and phenomena that have appeared in the context o
f non-equilibrium evolution in isolated systems. I will end by focusing o
n a specific example\, namely\, the dynamics of composite objects in latti
ce systems. such as repulsively bound pairs\, triplets and clusters.\n\n//
indico.ictp.it/event/a1373/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1373/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Information-theoretic vs
. thermodynamic entropy production in autonomous sensory networks"\n\n
DTSTART;VALUE=DATE-TIME:20130320T140000Z
DTEND;VALUE=DATE-TIME:20130320T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1377@ictp.it
DESCRIPTION:For sensory networks\, we determine the rate with which they a
cquire information about the changing external conditions. Comparing this
rate with the thermodynamic entropy production that quantifies the cost of
maintaining the network\, we find that there is no universal bound restri
cting the rate of obtaining information to be less than this thermodynamic
cost. These results are obtained within a general bipartite model consist
ing of a stochastically changing environment that affects the instantaneou
s transition rates within the system. Moreover\, they are illustrated \nw
ith a simple four-states model motivated by cellular sensing. On the techn
ical level\, we obtain an upper bound on the rate of mutual information an
alytically and calculate this rate with a numerical method that estimates
the entropy of a time-series generated with a simulation.\n\n//indico.ict
p.it/event/a1377/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1377/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Irreversibl
e work\, large deviations\, critical Casimir effect\, and universality in
quantum quenches"\n
DTSTART;VALUE=DATE-TIME:20130321T103000Z
DTEND;VALUE=DATE-TIME:20130321T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1372@ictp.it
DESCRIPTION:Recent experimental progress in the physics of ultracold atomi
c gases has revived the interest in the behavior of thermally isolated qua
ntum statistical systems\, especially after sudden changes (quenches) of t
heir control parameters. Considering the quench as a thermodynamic transf
ormation\, it is natural to focus on the irreversible work done on the sys
tem\, which is characterized by a certain probability distribution. By st
udying its large deviations\, i.e.\, rare fluctuations of the work per uni
t volume\, we establish a connection with the physics of a classical syste
m confined in a film geometry. If the system is quenched close to a (quan
tum) critical point\, both the edge singularity and the large deviations o
f the irreversible work acquire universal features dictated by the critica
l Casimir effect in the corresponding classical system. In systems of bos
ons\, the statistics of the work may additionally display a transition whi
ch is analogous to the equilibrium Bose-Einstein condensation.\n\n//indico
.ictp.it/event/a1372/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1372/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "On the carr
ier multiplication in graphene"\n
DTSTART;VALUE=DATE-TIME:20130328T090000Z
DTEND;VALUE=DATE-TIME:20130328T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1380@ictp.it
DESCRIPTION:We study relaxation of an excited electron in the conduction b
and of intrinsic graphene at zero temperature due to production of interba
nd electron-hole pairs by Coulomb interaction. The electronic band curvat
ure\, being anisotropic because of trigonal warping\, is shown to suppress
relaxation for a range of directions of the initial electron momentum. Fo
r other directions\, relaxation is allowed only if the curvature exceeds a
finite critical value\; otherwise\, a non-decaying quasiparticle state is
shown to exist.\n\n//indico.ictp.it/event/a1380/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1380/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar: "Infinitely disordered critical behaviour"
DTSTART;VALUE=DATE-TIME:20130328T103000Z
DTEND;VALUE=DATE-TIME:20130328T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1384@ictp.it
DESCRIPTION:Spatial inhomogeneities\, e.g. dislocations or impurities are
inevitable features of realistic systems. In condensed matter physics\, th
e dynamics of disorder is usually slow compared to experimental time scale
s\, thus inhomogeneities are well approximated by time-independent\, quenc
hed disorder. Although being a microscopic perturbation\, quenched disord
er may dramatically change the large-scale critical behavior of the system
. A paradigmatic example is the zero temperature quantum phase transition
of the quantum Ising model\, where the system exhibits exotic\, infinitely
disordered critical behavior. Besides the quantum Ising model\, there is
a huge number of further interesting examples\, such as the random walk in
1D\, the 1D Hubbard model\, the Mott metal-insulator transition in 2D\, l
ocalization of a random polymer at an interface\, random exclusion process
es and trap models\, driven lattice gases and reaction diffusion models\,
as well as a number of classical and quantum spin systems. In the underst
anding of the phenomena the strong disorder renormalization group (SDRG) m
ethod plays a crucial role\, yielding exact analytical results in 1D. Unfo
rtunately\, in higher dimensional systems the method is only numerically a
pplicable. In 2D this enabled to study only relatively small systems with
a limited accuracy. In the experimentally important three dimensional cas
e no quantitative results have been achieved.\nIn this talk I will give an
overview about my analytical and numerical results concerning the SDRG me
thod\, leading to the first quantitative results in 3 (and higher) dimensi
ons. The obtained results are directly applicable also for the contact pro
cess\, which is a simple model of infection spreading.\n\n//indico.ictp.it
/event/a1384/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1384/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar on Statistical Physics: "Non-equilibrium statistic
al mechanics: A growing frontier of 'pure and applied' theoretical physics
"
DTSTART;VALUE=DATE-TIME:20130403T130000Z
DTEND;VALUE=DATE-TIME:20130403T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1387@ictp.it
DESCRIPTION:Founded over a century ago\, statistical mechanics (SM) for sy
stems in thermal equilibrium has been so successful that\, nowadays\, it f
orms part of our physics core curriculum. On the other hand\, most of "re
al life" phenomena occur under non-equilibrium conditions.\nUnfortunately\
, statistical mechanics for such systems is far from being well establishe
d. The goal of understanding complex collective behavior from simple micro
scopic rules (of evolution\, say) remains elusive. As an example of the di
fficulties we face\, consider predicting the existence of a tree from an a
ppropriate collection of H\,C\,O\,N\,... atoms!\nOver the last two decades
\, an increasing number of condensed matter theorists are devoting their e
fforts to this frontier. After a brief summary of the crucial differences
between text-book equilibrium SM and non-equilibrium SM\, I will give a bi
rd's-eye view of some key issues\, ranging from the "fundamental" to (a sm
all set of) the "applied." The methods used also span a wide spectrum\, fr
om "easy" computer simulations to sophisticated field theoretic techniques
. These will be illustrated in the context of an overview of our work\, as
well as a simple Ising model coupled to two thermal baths.\n\n//indico.ic
tp.it/event/a1387/
LOCATION:SISSA\, Santorio Building\, Room 5 (ground floor)
URL://indico.ictp.it/event/a1387/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Melting tra
nsition of hard disks: New algorithms\, new insights "\n
DTSTART;VALUE=DATE-TIME:20130404T103000Z
DTEND;VALUE=DATE-TIME:20130404T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1385@ictp.it
DESCRIPTION:The hard-disk model has exerted outstanding influence on compu
tational physics and statistical mechanics. Decades ago\, hard disks were
the first system to be studied by Markov-chain Monte Carlo methods and by
molecular dynamics. It was in hard disks\, through numerical simulations
\, that a two-dimensional melting transition was first seen to occur even
though such systems cannot develop long-range crystalline order. Analysis
of the system was made difficult by the absence of adequate simulation me
thods.\nIn recent years\, we have developed a number of powerful Monte Ca
rlo algorithms for hard disks and related systems. I will in particular sh
ow how the powerful event-chain Monte Carlo algorithm has allowed us to\n
show that hard disks melt with a first-order transition from the liquid t
o the hexatic and a continuous transition from the hexatic to the solid. I
will finish with discussions on the general theory of two-dimensional mel
ting and on the generalizations of the event-chain algorithm.\n\n//indico.
ictp.it/event/a1385/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1385/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Why do complex syst
ems look critical"
DTSTART;VALUE=DATE-TIME:20130409T103000Z
DTEND;VALUE=DATE-TIME:20130409T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1390@ictp.it
DESCRIPTION:The study of complex systems is limited by the fact that only
few variables are accessible for modeling and sampling\, which are not nec
essarily the most relevant ones. In addition\, empirical data typically un
der sample the space of possible states.\nWe study a class of complex syst
ems\, which are systems of many interacting degrees of freedom\, which are
known only in part\, that optimize a given function. We show that the inf
ormation that a sample contains on the behavior of the system is quantifie
d by the entropy of the frequency with which different states occur. This
allows us to characterize the properties of maximally informative samples:
\nIn the under-sampling regime\, the most informative frequency size distr
ibutions have power law behavior and Zipf's law emerges at the crossover b
etween the under sampled regime and the regime where the sample contains e
nough statistics to make inference on the behavior of the system. These id
eas are illustrated in some applications\, showing that they can be used t
o identify relevant variables or to select most informative representation
s of data\, e.g. in data clustering.\n\n//indico.ictp.it/event/a1390/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1390/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"Difference
between ergodicity\, level statistics and localization transitions on the
Bethe lattice"
DTSTART;VALUE=DATE-TIME:20130411T104000Z
DTEND;VALUE=DATE-TIME:20130411T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1389@ictp.it
DESCRIPTION:Random Matrix Theory was initially developed to explain the ei
gen-energy distribution of heavy nuclei. It has become clear by now that i
ts domain of application is much broader and extends to very different fie
lds such as number theory and quantum chaos\, just to cite a few. In parti
cular\, it has been conjectured—and proved or verified in some special c
ases—that quantum ergodic (or chaotic) systems are characterized by eige
n-energies statistics in the same universality class of random matrices an
d by eigen-functions that are delocalized over the configuration space. On
the contrary\, non-ergodic quantum systems\, such as integrable models\,
are expected to display a Poisson statistics of energy levels and localize
d wave-functions. Starting from Anderson’s pioneering papers\, similar p
roperties have also been studied for electrons hopping in a disordered env
ironment. Remarkably\, also in this case\, similar features of the energy-
level statistics have been found. All that has lead to the conjecture that
delocalization in configuration space\, ergodicity and level statistics a
re intertwined properties. \nIn this talk we revisit the old problem of no
n-interacting electrons hopping on a Bethe lattice with on-site disorder.
By using numerical simulations\, the cavity method and mapping to directed
polymers in random media we unveil the existence of an intermediate phase
in which wave-functions are delocalized but the energy-level statistics i
s Poisson. This new phase\, in which the system is non-ergodic but delocal
ized\, may play an important role in several fields from random matrix the
ory to strongly interacting quantum disordered systems\, in particular it
could be related to the non-ergodic metallic phase conjectured to exist in
the context of Many-Body Localization.\n\n//indico.ictp.it/event/a1389/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1389/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Thermodynamics of p
rediction"
DTSTART;VALUE=DATE-TIME:20130416T100000Z
DTEND;VALUE=DATE-TIME:20130416T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1395@ictp.it
DESCRIPTION:I will discuss the fundamental equivalence between thermodynam
ic inefficiency\, measured by dissipation\, and information processing ine
fficiency. The dynamics of any system responding to a stochastic environme
ntal signal can be interpreted as computing an implicit model of the drivi
ng signal. The system’s state retains information about past environment
al fluctuations\, and a fraction of this information is predictive of futu
re fluctuations. The remaining nonpredictive information reflects model co
mplexity that does not improve predictive power\, and thus represents the
inefficiency of the model. We find that instantaneous nonpredictive inform
ation: 1) is proportional to the work dissipated due to environmental chan
ge\; 2) provides a lower bound on the total dissipated work when summed ov
er the length of a driving protocol\; 3) augments the lower bound on heat
generated due to information erasure (Landauer's principle). Our results h
old far from thermodynamic equilibrium and are thus applicable to a wide r
ange of systems\, including biomolecular machines\, and potential future n
ano computing devices. These results highlight a profound connection betwe
en the effective use of information and efficient thermodynamic operation:
any system constructed to keep memory about its environment\, and to oper
ate with maximal energetic efficiency\, has to be predictive. http://prl.a
ps.org/abstract/PRL/v109/i12/e120604\n\n//indico.ictp.it/event/a1395/
LOCATION:SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a1395/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Applied Mathematics/Statistical Mechanics seminar
: "Shocks in fragile matter"
DTSTART;VALUE=DATE-TIME:20130417T120000Z
DTEND;VALUE=DATE-TIME:20130417T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1391@ictp.it
DESCRIPTION:Non-linear sound is an extreme phenomenon typically observed i
n solids after violent explosions. But granular media are different. Right
when they unjam\, these fragile and disordered solids exhibit vanishing e
lastic moduli and sound speed\, so that even tiny mechanical perturbations
form supersonic shocks. Here\, we perform simulations in which two-dimens
ional jammed granular packings are continuously compressed\, and demonstra
te that the resulting excitations are strongly nonlinear shocks\, rather t
han linear waves. We capture the full dependence of the shock speed on pre
ssure and compression speed by a surprisingly simple analytical model. We
also treat shear shocks within a simplified viscoelastic model of nearly-i
sostatic random networks comprised of harmonic springs. In this case\, anh
armonicity does not originate locally from nonlinear interactions between
particles\, as in granular media\; instead\, it emerges from the global ar
chitecture of the network. As a result\, the diverging width of the shear
shocks bears a nonlinear signature of the diverging isostatic length assoc
iated with the loss of rigidity in these floppy networks.\n\n//indico.ictp
.it/event/a1391/
LOCATION:SISSA\, Santorio Building\, Room 4 (ground floor)
URL://indico.ictp.it/event/a1391/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Mass-algebr
as and the quantum numbers of topological defects in Dirac systems"\n
DTSTART;VALUE=DATE-TIME:20130418T103000Z
DTEND;VALUE=DATE-TIME:20130418T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a1397@ictp.it
DESCRIPTION:I will discuss the Dirac quasiparticles in the lattice systems
of electrons\, exemplified by graphene\, in the presence of topological d
efects of the allowed order parameters. These orders appear as possible m
ass terms in the Dirac equation\, and their topological defects have been
known to carry non-trivial quantum numbers such as fractionalized charge s
ince the work of Jackiw and Rebby in 1976. In the talk I will discuss the
ir additional internal degree of freedom: irrespectively of the nature of
orders that support the defect\, an extra mass-order-parameter spontaneous
ly emerges in the defect's core. The determination of the quantum state o
f the topological defect in Dirac systems turns out to be an interesting p
roblem in the (real) representation theory of Clifford algebras\; with the
Clifford algebra C(2\,5) playing a fundamental role in graphene\, for exa
mple. Ultimately\, the particle-hole symmetry restricts the defects to al
ways carry the quantum numbers of a single effective "isospin" - 1/2\, qui
te independently of the values of their electric charge or true spin. Exa
mples of this new degree of freedom in graphene and other Dirac-like syste
ms\, such as graphene bilayers or d-wave superconductors will be given.\n\
n//indico.ictp.it/event/a1397/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a1397/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Landau - Zener inte
rferometry with double and triple quantum dots"\n
DTSTART;VALUE=DATE-TIME:20130423T103000Z
DTEND;VALUE=DATE-TIME:20130423T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13100@ictp.it
DESCRIPTION:In this talk I will review general non-adiabatic theories of t
wo- and three- level crossings subject to fast and slow Gaussian noise.\nT
he applications to recent experiments on Landau - Zener interferometry in
double/triple quantum dots and superconducting qubits will be discussed.\n
\n//indico.ictp.it/event/a13100/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13100/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Conduction
properties of ultracold Fermions"
DTSTART;VALUE=DATE-TIME:20130425T103000Z
DTEND;VALUE=DATE-TIME:20130425T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13101@ictp.it
DESCRIPTION:We experimentally study the transport process of ultracold fer
mionic atoms through a mesoscopic\, quasi two-dimensional channel connecti
ng macroscopic reservoirs. By observing the current response to a bias ap
plied between the reservoirs\, we directly access the resistance of the ch
annel in a manner analogous to a solid state conduction measurement. The
resistance is further controlled by a gate potential reducing the atomic d
ensity in the channel\, like in a field effect transistor. In this setup\
, we study the flow of a strongly interacting Fermi gas\, and observe a st
riking drop of resistance with increasing density in the channel\, as expe
cted at the onset of superfluidity. The resistance is compared to that of
an ideal Fermi gas in the same geometry\, which shows an order of magnitu
de larger resistance\, originating from the contact resistance between the
channel and the reservoirs. We extended this investigation to disordered
superfluids and provide evidences for a disorder-induced breakdown of sup
erfluidity.\n\n//indico.ictp.it/event/a13101/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13101/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Localizatio
n of bound states in quasi-periodic optical lattices"\n
DTSTART;VALUE=DATE-TIME:20130502T103000Z
DTEND;VALUE=DATE-TIME:20130502T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13105@ictp.it
DESCRIPTION:We discuss the formation of bound states made of two interacti
ng atoms moving in a one dimensional (1D) quasi-periodic optical lattice.\
nThe underlying hamiltonian is the Aubry-André model with additional on-s
ite interactions.\nWe derive the quantum phase diagram for localization of
both attractively and repulsively bound pairs. We calculate the pair bind
ing energy and show analytically that its behavior as a function of the in
teraction strength depends crucially on the nature -extended\, multifracta
l\, localized- of the single-particle atomic states. Experimental implicat
ions of our results are discussed.\n\nRef: G. Dufour\, G. Orso\, Phys. Rev
. Lett. 109\, 155306 (2012)\n\n//indico.ictp.it/event/a13105/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13105/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Empirical portfolio sel
ection"
DTSTART;VALUE=DATE-TIME:20130507T133000Z
DTEND;VALUE=DATE-TIME:20130507T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13106@ictp.it
DESCRIPTION:In this seminar we survey discrete time\, multi period\, sequ
ential investment strategies for financial markets.\nUnder memoryless ass
umption on the underlying process generating the asset prices the Best Con
stantly Rebalanced Portfolio is studied\, called log-optimal portfolio\, w
hich achieves the maximal asymptotic average growth rate. For generalized
dynamic portfolio selection\, when asset prices are generated by a statio
nary and ergodic process\, universally consistent empirical methods are sh
own\, using current principles of nonparametric regression estimation and
machine learning algorithms.\nThe empirical performance of the methods are
illustrated for NYSE data.\n\n//indico.ictp.it/event/a13106/
LOCATION:ICTP Adriatico Guest House Denardo Lecture Hall
URL://indico.ictp.it/event/a13106/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: “Active fluids: Fr
om Liquid Crystals to Living Systems”\n
DTSTART;VALUE=DATE-TIME:20130507T100000Z
DTEND;VALUE=DATE-TIME:20130507T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13125@ictp.it
DESCRIPTION:Colonies of motile microorganisms\, the cytoskeleton and its c
omponents\, cells and tissues have much in common with soft condensed mat
ter systems \n(i.e. liquid crystals\, amphiphiles\, colloids etc.)\, but a
lso exhibit behaviors that do not appear in inanimate matter and that are
crucial for biological functions. These unique properties arise when the c
onstituent particles are active: they consume energy from internal and ex
ternal sources and dissipate it by moving through the medium they inhabit.
In this talk I will give a brief introduction to the notion of "active
matter" and present some recent results on the hydrodynamics of active ne
matics suspensions in two dimensions.\n\n//indico.ictp.it/event/a13125/
LOCATION:SISSA\, Santorio Building room 128 (1st floor)
URL://indico.ictp.it/event/a13125/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: “Magnetotr
ansport in Non-magnetic Inhomogeneous Materials”\n
DTSTART;VALUE=DATE-TIME:20130509T103000Z
DTEND;VALUE=DATE-TIME:20130509T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13126@ictp.it
DESCRIPTION:A substantial magnetodielectric effect is usually an indicatio
n of coupled magnetic and elastic order\, such as is found in the multifer
roics. However\, here I will show that magnetism is not necessary to produ
ce either a magnetoresistance or a magnetocapacitance when the material is
inhomogeneous. From exact calculations and numerical simulations of metal
-dielectric composites\, I find a characteristic dielectric resonance that
sensitively depends on magnetic field. I will discuss how this behaviour
has already been observed experimentally in some materials.\n\n//indico.ic
tp.it/event/a13126/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13126/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Colloquium on Condensed Matter Physics: "Correlat
ed electron calculations with polynomial scaling"\n
DTSTART;VALUE=DATE-TIME:20130515T150000Z
DTEND;VALUE=DATE-TIME:20130515T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13124@ictp.it
DESCRIPTION:Due to its simplicity and numerical efficiency\, density funct
ional theory (DFT) is the most popular approach for calculating the electr
onic structure of large molecules and materials. Nevertheless\, the accura
cy of DFT is not always satisfactory and the search for improved approxima
tions that avoid self-interaction and capture strong electron correlations
faces severe difficulties. In this talk I will present an alternative app
roach in which the one- and two-particle density matrices needed to comput
e the ground-state energy\, are explicit functionals of the natural spin o
rbital states and their joint occupation probabilities. The scheme is para
meter-free and not affected by self-interaction error. In its simplest for
mulation\, restricted to the seniority zero sector of the many-particle Hi
lbert space\, it has the same scaling of Hartree-Fock theory. Yet\, it des
cribes strong correlations as demonstrated by calculating the dissociation
energy curves of diatomic molecules and linear chains of hydrogen atoms.
Improved approximations that retain polynomial cost but are not limited to
seniority zero will be also discussed.\n\n//indico.ictp.it/event/a13124/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13124/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Functional
renormalization group in and out of equilibrium"\n\n
DTSTART;VALUE=DATE-TIME:20130516T124500Z
DTEND;VALUE=DATE-TIME:20130516T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13127@ictp.it
DESCRIPTION:For quantum systems specified by a given density matrix at ini
tial time\, a generating functional for real-time correlation functions ca
n be written down using the Schwinger-Keldysh closed time path. This can b
e used to construct a nonequilibrium functional renormalization group alon
g similar lines as for Euclidean field theories in thermal equilibrium. I
mportant differences include the absence of a fluctuation-dissipation rela
tion for general out-of-equilibrium situations. The nonequilibrium renorm
alization group takes on a particularly simple form at a fixed point\, whe
re the corresponding scale-invariant system becomes independent of the det
ails of the initial density matrix. This can be used to derive a hierarch
y of fixed point solutions with increasing complexity from vacuum and ther
mal equilibrium to nonequilibrium. The application to dynamic critical ph
enomena and the phenomenon of turbulence in quantum field theory will be d
iscussed.\n\n//indico.ictp.it/event/a13127/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13127/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Ultra-cold atoms as
universal quantum simulators: Symmetry locked superfluid phases"
DTSTART;VALUE=DATE-TIME:20130521T103000Z
DTEND;VALUE=DATE-TIME:20130521T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13137@ictp.it
DESCRIPTION:I review the concept of ultra-cold atoms as universal quantum
simulators for quantum many body systems\, focusing on motivations\, main
targets and open problems. As a realistic example I then describe a setup
of ultracold fermionic mixtures in optical lattices able to host superflui
d phases with symmetry obtained by locking independent invariance groups o
f the normal state. Due to their peculiar symmetry\, these phases can also
show exotic soliton structures\, as vortices with semi-integer flux and g
apless non-Abelian Goldstone modes localized on them. The origin of the no
n-abelianity\, the braiding properties\, the mechanism and the consequence
s of fractionality for such vortices are discussed. The scenario proposed
displays remarkable similarities to what arises in ultra-dense QCD matter\
, as in the core of some neutron stars. A discussion about the experimenta
l detection of locked phases and non-abelian fractional vortices is as wel
l provided.\n\n//indico.ictp.it/event/a13137/
LOCATION:ICTP Adriatico Guest House Giambiagi Lecture Hall
URL://indico.ictp.it/event/a13137/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Colloquium on Condensed Matter Physics: "First pr
inciples simultations of materials and processes in photocatalysis"
DTSTART;VALUE=DATE-TIME:20130522T150000Z
DTEND;VALUE=DATE-TIME:20130522T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13136@ictp.it
DESCRIPTION:In this talk I will discuss applications of first principles e
lectronic structure calculations and molecular dynamics simulations to und
erstand materials properties and reaction mechanisms relevant to photocaly
sis and energy applications. Examples will focus on the surface properties
of TiO2\, a widely used photocatalyst capable of splitting water in O2 +
H2\, and hydrogen production from water by the active site of an enzyme
of hydrogen-producing bacteria\, the di-iron hydrogenase\, linked to a pyr
ite electrode.\n\n//indico.ictp.it/event/a13136/
LOCATION:SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a13136/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar: " The summer of our discontent - the banking scan
dals of 2012 "\n
DTSTART;VALUE=DATE-TIME:20130523T160000Z
DTEND;VALUE=DATE-TIME:20130523T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13138@ictp.it
DESCRIPTION:In the summer of 2012\, a series of scandals broke out around
the largest\, systemically most important banks of the world. In most cas
es\, the roots and practice of misdeeds (Libor rigging\, violations of s
anctions\, money laundering\, mis-selling of fake products\, tax fraud\, i
nsider trading\, etc.) go back several years. Regulators imposed record fi
nes on the banks\, in a few cases started criminal procedures against the
most incriminated players\, and a deluge of lawsuits was launched. The reg
ulators raised questions about the responsibility of rating agencies and c
onsultants\, but in some cases the scandals shed a dubious light on the re
gulators themselves\, as well as on the British and US governments\, and a
lso the American Congress.\nThe talk reviews some of the elements of this
series of scandals\, and tries to draw some conclusions for regulation.\n\
n//indico.ictp.it/event/a13138/
LOCATION:ICTP Adriatico Guest House Giambiagi Lecture Hall
URL://indico.ictp.it/event/a13138/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Scrutinizing the co
smological constant problem and a proposal"
DTSTART;VALUE=DATE-TIME:20130523T103000Z
DTEND;VALUE=DATE-TIME:20130523T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13139@ictp.it
DESCRIPTION:We suggest a new perspective on the Cosmological Constant Prob
lem by scrutinizing its standard formulation. In classical and quantum mec
hanics without gravity\, there is no definition of the zero point of energ
y. Furthermore\, the Casimir effect only measures how the vacuum energy ch
anges as one varies a geometric modulus. This leads us to propose that the
physical vacuum energy in a Friedman-Lemaitre-Robertson-Walker expanding
universe only depends on the time variation of the scale factor $a(t)$. Eq
uivalently\, requiring that empty Minkowski space is gravitationally stabl
e is a principle that fixes the ambiguity in the zero point energy. On the
other hand\, if there is a meaningful bare cosmological constant\, this p
rescription should be viewed as a fine-tuning. We describe two different c
hoices of vacuum\, one of which is consistent with the current universe co
nsisting only of matter and vacuum energy. The resulting vacuum energy den
sity is constant in time and approximately kc2 H02\, where kc is a momentu
m cut-off and H0 is the current Hubble constant\; for a cut-off close to t
he Planck scale\, values of vacuum energy density in agreement with astrop
hysical measurements are obtained. Another choice of vacuum is more releva
nt to the early universe consisting of only radiation and vacuum energy\,
and we suggest it as a possible model of inflation.\n\n//indico.ictp.it/ev
ent/a13139/
LOCATION:SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a13139/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar: "Transition metal dopants in other metal cluster
s: From shell model to magnetic superatoms and beyond"\n
DTSTART;VALUE=DATE-TIME:20130528T130000Z
DTEND;VALUE=DATE-TIME:20130528T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13141@ictp.it
DESCRIPTION:I will start with the idea of electronic shell models as propo
sed for simple metal clusters\, and show how this leads to the idea of sup
eratoms. I will then present our work on 3d transition metal (TM) doped al
kali and alkaline earth clusters and show how the ideas of electronic shel
l models play out in these. This will lead us to magnetic superatoms. I wi
ll also point out how a subtle interplay of crystal field effect and excha
nge coupling leads to enhanced stability for certain TM-alkaline earth clu
sters\, and leads to new magnetic superatoms in this series. Time permitti
ng\, I will present some of our recent results on TM-doped aluminum cluste
rs and will argue that aromaticity rather than shell models plays a role i
n these clusters.\n\n//indico.ictp.it/event/a13141/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13141/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Boltzmann pseudodyn
amics for spin glasses and liquids"\n
DTSTART;VALUE=DATE-TIME:20130528T103000Z
DTEND;VALUE=DATE-TIME:20130528T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13146@ictp.it
DESCRIPTION:More than 10 years ago\, it was realized that mean field glass
y dynamics\, with the emergence of aging and effective temperatures\, can
be understood as quasi-equilibrium exploration of configuration space. The
formalization of this notion\, only recently proposed\, defines a Markov
chain where short times are coarse grained\, and subsequent configurations
are chosen according to a constrained Boltzmann distribution.\n\nIn mean
field spin glasses\, this pseudodynamic rule admits\, in the long time lim
it\, a description leading to glassy solutions identical to the ones corre
sponding to real (Langevin) dynamics. The treatment of the pseudodynamics
through replicas unveils a longly suspected relation between replicas and
the supersymmetry of the Langevin equation.\n\nThe application of the form
alism to liquids avoids the difficulties related to short time conservatio
n laws\, and allows to use equilibrium approximation schemes of liquid the
ory to study long time dynamics. The scheme is applied to a closure scheme
of hierarchical equations recently proposed by Szamel and to liquids in t
he hypernetted chain (HNC) approximation. It is shown that the former case
leads to the standard Mode Coupling Theory (MCT) equations of Gœtze\, th
us giving an interpretation of it. The second case also gives rise to MCT-
like equations\, but in a framework where\, differently from MCT that requ
ires the input of equilibrium structure factors\, static equilibrium and d
ynamical quantities are computed in a unified consistent framework.\n\nRef
s. SF and G. Parisi\, JSTAT P02003 (2013)\, SF\, G. Parisi and P. Urbani\,
arXiv:1212.4291\n\n//indico.ictp.it/event/a13146/
LOCATION:ICTP Adriatico Guest House Giambiagi Lecture Hall
URL://indico.ictp.it/event/a13146/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Hall-drag a
nd magneto-drag in graphene via kinetic equation approach"\n\n
DTSTART;VALUE=DATE-TIME:20130530T103000Z
DTEND;VALUE=DATE-TIME:20130530T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13145@ictp.it
DESCRIPTION:Recently\, Coulomb drag measurements have been performed in gr
aphene\, usually in the presence of magnetic fields as well. In this work
we calculate the magneto-drag and the Hall-drag resistivity at finite tem
perature for two graphene monolayers by solving the quantum kinetic equati
on. The presented theory is valid in the hydrodynamic regime\, which is d
ominated by inelastic scattering. The microscopic formulation supports a p
henomenological Drude-like picture which for large concentrations equals t
he usual Drude form\, and for small concentration an effective two-band-Dr
ude equation. Our theory allows for a qualitative description for arbitra
ry chemical potentials. An emphasis is put on the Hall-drag which is abse
nt when derived from the standard Drude equation. We show that the Hall-d
rag vanishes along the line of opposite carrier concentration in the layer
s\, but we also identify non trivial concentrations at which the Hall-drag
vanishes.\n\n//indico.ictp.it/event/a13145/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13145/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: Momentum transfer in
non-equilibrium steady states
DTSTART;VALUE=DATE-TIME:20130604T103000Z
DTEND;VALUE=DATE-TIME:20130604T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13316@ictp.it
DESCRIPTION://indico.ictp.it/event/a13316/
LOCATION:ICTP Adriatico Guest House Giambiagi Lecture Hall
URL://indico.ictp.it/event/a13316/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Condensed Matter Seminar:\nDuality Near the Super
conductor-Insulator Transition
DTSTART;VALUE=DATE-TIME:20130605T150000Z
DTEND;VALUE=DATE-TIME:20130605T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13148@ictp.it
DESCRIPTION:Careful transport measurements near the superconductor-insulat
or transition in amorphous indium-oxide reveal a symmetry relating states
in the insulator to those in the superconducting phase. I will discuss thi
s symmetry and its consequences\, and show that it is violated upon enteri
ng\nthe strong insulator at low temperatures.\n\n//indico.ictp.it/event/a1
3148/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13148/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and Strong Electron Correlations: New Paths to
Unconventional Topological Superconductivity
DTSTART;VALUE=DATE-TIME:20130606T103000Z
DTEND;VALUE=DATE-TIME:20130606T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13149@ictp.it
DESCRIPTION:We report on our recent progress regarding classes of material
s which exhibit chiral triplet and singlet superconductivity\, where topol
ogically nontrivial \npairing phenomena can emerge. Specifically\, motivat
ed by recent experimental advances\, we show that graphene doped to the va
n Hove regime can give rise to a plethora of interesting ordering instabil
ities such as spin density wave and superconductivity. As a function of sy
stem\nparameters such as doping and range of Coulomb \ninteraction\, we ex
plain which instability is favored by the system\, and analyze the effect
of long-range interactions on superconductivity giving rise to a competiti
on\nbetween singlet d+id and triplet f wave. We further \nreport on our in
vestigations of Cobaltate superconductors where we believe the experimenta
l evidence can be reconciled by an anisotropic d+id superconducting gap. \
nWe also outline our work in progress for other compounds such as strontiu
m ruthenate and SrPtAs which we believe\nare promising to stabilize such i
nteresting topological superconducting states of matter.\n\n//indico.ictp.
it/event/a13149/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13149/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar. Many-body Localizat
ion. Building a Theory of a Quantum Glass
DTSTART;VALUE=DATE-TIME:20130611T103000Z
DTEND;VALUE=DATE-TIME:20130611T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13155@ictp.it
DESCRIPTION://indico.ictp.it/event/a13155/
LOCATION:ICTP Adriatico Guest House Giambiagi Lecture Hall
URL://indico.ictp.it/event/a13155/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and Strong Electron Correlations. "Induced Sup
erconductivity in Graphene"
DTSTART;VALUE=DATE-TIME:20130613T103000Z
DTEND;VALUE=DATE-TIME:20130613T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13158@ictp.it
DESCRIPTION:I will present theoretical results on induced\nsuperconductivi
ty in graphene covered by low \ndensity of small (sub-micron) islands of
\nsuperconducting metal.\nThen I present some of recently obtained \nexper
imental data on graphene with tin islands\nand discuss the comparison betw
een the data and\nthe theory.\n\n//indico.ictp.it/event/a13158/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13158/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Condensed Matter Seminar. Quantum Spin Squeezing
DTSTART;VALUE=DATE-TIME:20130620T103000Z
DTEND;VALUE=DATE-TIME:20130620T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13159@ictp.it
DESCRIPTION:Abstract: I will give a brief introduction about quantum sque
ezing\, and discuss properties of some definitions of the spin squeezing p
arameter. Then I will show some recent results of our group for the time d
ependent squeezing parameter in different systems: Cavity QED\, spin chain
s\, and quantum corrals.\n\n//indico.ictp.it/event/a13159/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13159/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Mechanics Seminar. "Optimal Design fo
r Quantum Transport Across a Disordered System"
DTSTART;VALUE=DATE-TIME:20130625T103000Z
DTEND;VALUE=DATE-TIME:20130625T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13161@ictp.it
DESCRIPTION:For more than 50 years we have known that photosynthetic syste
ms harvest solar energy with almost unit quantum efficiency. However\, rec
ent experimental evidence of quantum coherence during the excitonic energy
transport in photosynthetic organisms challenges our understanding of thi
s fundamental biological function. Currently\, and despite numerous effort
s\, the causal connection between coherence and efficiency is still a matt
er of debate. We show\, through extensive simulations of quantum coherent
transport on networks\, that three dimensional structures characterized by
centro-symmetric Hamiltonians are statistically more efficient than rando
m arrangements. Moreover\, we theoretical derive a general mechanism for h
ighly efficient quantum transport through nite\, disordered 3D networks. I
t relies on the interplay of disorder with centro-symmetry and a dominant
doublet spectral structure\, and can be controlled by proper tuning of onl
y coarse-grained quantities. Photosynthetic light harvesting complexes are
discussed as potential biological incarnations of this design principle.\
n\n//indico.ictp.it/event/a13161/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13161/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Associate CMSP seminar: "Quantum Ising dynamics and Majorana-like
edge modes in the Rabi lattice model”
DTSTART;VALUE=DATE-TIME:20130626T150000Z
DTEND;VALUE=DATE-TIME:20130626T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13170@ictp.it
DESCRIPTION:We present a case for the realization of Majorana-like edge mo
des\, through the quantum Ising (QI) dynamics\, in the Rabi lattice. A Rab
i lattice is an array of the Rabi quantum cavities where each cavity has a
two-level atom (or a spin-1/2) coupled via dipole interaction to a single
photon (bosonic) mode\, and the inter-cavity coupling causes photon hoppi
ng. We show that the Rabi lattice model rigorously tends to the QI model i
n the limit of strong atom-photon coupling. This QI dynamics drives the pa
ra- to ferro-electric quantum phase transition in the Rabi lattice\, and a
lso guarantees two Majorana-like edge modes in the ordered phase on an ope
n chain. We identify an observable signature of these modes\, and check th
eir stability against the detrimental perturbations such as a stray electr
ic field. We find that the QI Majorana modes are not as fragile as one bel
ieved\, despite no topological protection.\n\n//indico.ictp.it/event/a1317
0/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13170/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Disordered
bosons"
DTSTART;VALUE=DATE-TIME:20130718T103000Z
DTEND;VALUE=DATE-TIME:20130718T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13180@ictp.it
DESCRIPTION:Abstract\n \nI will discuss the global phase diagram of the di
sordered Bose-Hubbard model in all dimensions controlled by the theorem of
inclusions. In 1D\, in the regime when strong disorder is more relevant t
han field quantization the superfluid--to--Bose-glass criticality is prece
ded by the prolonged logarithmically slow classical-field renormalization
flow of the superfluid stiffness at mesoscopic scales. With the system com
pressibility remaining constant\, the quantum nature of the system manifes
ts itself only in the renormalization of dilute weak links. The transition
point is still controlled by the proliferation of the instanton--anti-ins
tanton pairs when the Luttinger liquid parameter equals 3/2\, in accordanc
e with the universal quantum scenario.\n\n//indico.ictp.it/event/a13180/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13180/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and Strong Electron Correlations: "Localizatio
n at the Edge of 2D Topological Insulator by Kondo Impurities with Random
Anisotropies"
DTSTART;VALUE=DATE-TIME:20130801T103000Z
DTEND;VALUE=DATE-TIME:20130801T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13272@ictp.it
DESCRIPTION:We consider chiral electrons moving along the 1D helical edge
of a 2D topological insulator and interacting with a disordered chain of K
ondo impurities. Assuming the electron-spin couplings of random anisotropi
es\, we map this system to the problem of the pinning of the charge densit
y wave by the disordered potential. This mapping proves that arbitrary wea
k anisotropic disorder in coupling of chiral electrons with spin impuritie
s leads to the Anderson localization of the helical edge states [1].\n\n[1
] B.L. Altshuler\, I.L. Aleiner\, and V.I. Yudson\, preprint arXiv: 1306.2
626\n\n//indico.ictp.it/event/a13272/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13272/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "An analytic
ally tractable model of bad metals"
DTSTART;VALUE=DATE-TIME:20130815T103000Z
DTEND;VALUE=DATE-TIME:20130815T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13275@ictp.it
DESCRIPTION:Abstract\n\nWe discuss a model Kondo-type Hamiltonian represen
ting an analytically tractable version of the model used by Yin et.al.\, P
hys. Rev. B 86\, 2399 (2012) to explain the non-Fermi liquid behavior of i
ron chalcogenides and ruthenates in an intermediate energy range. We consi
der a regime where a complete screening of the local degrees of freedom pr
oceeds in two stages described by two characteristic energy scales T_K^orb
>> E_0. The first scale marks a screening of the orbital degrees of freed
om and the second one marks a crossover to the regime with coherent propag
ation of quasiparticles. We present analytical results for the specific he
at and magnetic susceptibility at T \n\n//indico.ictp.it/event/a13275/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13275/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Condensed Matter Seminar: Mesoscopic conductance fluctuat
ions at a helical edge of a topological insulator
DTSTART;VALUE=DATE-TIME:20130816T093000Z
DTEND;VALUE=DATE-TIME:20130816T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13276@ictp.it
DESCRIPTION:Abstract\nElastic backscattering of electrons moving along the
helical edge is prohibited by time-reversal symmetry (TRS). \nWe demonst
rate\, however\, that an ensemble of magnetic impurities may cause TRS-pre
serving quasi-elastic backscattering\, resulting in interference effects i
n the conductance. The characteristic energy transferred in a backscatteri
ng event is suppressed due to the RKKY interaction of localized spins (the
suppression is exponential in the total number of magnetic impurities). W
e predict the statistics of conductance fluctuations to differ from those
in the conventional case of a one-dimensional system with quenched disorde
r. \n\n\nReference:\nV.Cheianov\, L.Glazman\, Phys. Rev. Lett.\, 110\, 206
803. (2013)\n\n//indico.ictp.it/event/a13276/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a13276/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Associate's CMSP Seminar: "Ab-initio study of H-doping and Oxygen
vacancy in TiO2"
DTSTART;VALUE=DATE-TIME:20130827T100000Z
DTEND;VALUE=DATE-TIME:20130827T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13284@ictp.it
DESCRIPTION:Abstract:\nTitanium dioxide (TiO2¬) is a widely used material
with many industrial applications. Because of the photocatalytic activity
and environmental compatibility\, it has tremendous potential application
s in solar cells\, dye industries\, electronic devices\, sensors and trans
formers. Density functional - pseudopotential calculations were performed
to study the effect of hydrogen doping in bulk\, and also H-doping and oxy
gen vacancy on electronic structure and stability of (001) surface of TiO2
in the anatase phase. In the framework of ab-initio atomistic thermodynam
ic\, we argue that the anatase TiO2 prefers a defected oxygen layer termin
ation in the (001) direction. The obtained electronic structures indicate
that deep hydrogen doping in this stable termination creates a mid-gap sta
te about 0.52 eV below the conduction band and hence decreases the band ga
p of the system. This phenomenon may explain the enhanced photocatalytic a
ctivity of the anatase TiO2 (001) surface after hydrogenation.\n\n//indico
.ictp.it/event/a13284/
LOCATION:ICTP Adriatico Guest House Giambiagi Lecture Hall
URL://indico.ictp.it/event/a13284/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Associate's CMSP Seminar: "Insulator-AF and Pseudogap states joini
ng into a QPT beneath the superconducting “dome” from a model CuO pla
nes in La2CuPO4"
DTSTART;VALUE=DATE-TIME:20130827T103000Z
DTEND;VALUE=DATE-TIME:20130827T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13285@ictp.it
DESCRIPTION:Abstract:\nThe effect of hole doping on the Tight-Binding (TB
) model of the Cu-O planes in the La2CuO4 constructed in previous works is
investigated here. Firstly\, it is pointed out that the model employed co
nstitutes a generalization of the Hubbard one for the same system. Thus\,
the former predictions of the insulator gap\, antiferromagnetic (AF) chara
cter and the existence of a paramagnetic-pseudogap (PPG) state at half-fil
ling\, become natural ones to be expected from this more general picture.
The effect of hole doping on the antiferromagnetic-insulator state (AFI) a
nd the paramagnetic-pseudogap one at half-filling\, is investigated here a
t T = 0 K. The results predict the occurrence of a quantum phase transitio
n (QPT) from the antiferromagnetic- insulator state at low doping to a par
amagnetic-metallic state (PM) at higher hole densities. Therefore\, a clea
r description of the hidden QPT laying beneath the “dome” in high crit
ical temperature (HTc) superconducting materials is found. At low doping\,
the systems prefers the AFI state\, and at the critical value of the dopi
ng density dc = 0.2\, the energy of a metallic state starts becoming lower
. The evolution with small doping values of the band spectrum of the AFI s
tate\, shows that the holes tend to become localized at the middle of the
sides of the reduced Brillouin zone (BZ). Then\, when passes through the c
ritical value\, the holes of the AFI state move to become situated at the
corners of the same reduced BZ\, showing in this way a structural change a
t the phase transition point. It suggests that the Kramers degeneration in
combination with the spin-spatial entangled nature of the hole states\, c
an lead to a new kind of pair interaction between two holes. The binding e
nergy value is estimated as a function of the screening.\n\n//indico.ictp.
it/event/a13285/
LOCATION:ICTP Adriatico Guest House Giambiagi Lecture Hall
URL://indico.ictp.it/event/a13285/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Probing com
plexity in aqueous systems"\n
DTSTART;VALUE=DATE-TIME:20131010T103000Z
DTEND;VALUE=DATE-TIME:20131010T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13310@ictp.it
DESCRIPTION:Water is one of the most ubiquitous substances in the universe
. Despite long study from both experimental and theoretical approaches\,
phenomena associated with liquid water and its coupling to other systems c
ontinues to be a source of rather rich and interesting physics. In this t
alk\, I will discuss how computational studies play an important role in p
robing both the structure and dynamics of water in different environments.
I will motivate the discussion by briefly talking about water near the v
icinity of proteins and the coupling between protein and water motions. I
will then move onto some more recent work on trying to understand water a
s a hydrogen bond network and its subsequent role on processes like proton
transfer in liquid water and anomalous water diffusion around ions like C
sI and NaCl. I will also briefly touch on the role of nuclear quantum eff
ects in altering the structural and electronic properties of water and its
constituent ions.\n\n//indico.ictp.it/event/a13310/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a13310/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Superfluid-
insulator transition and the phase dynamics of two-species bosons with spi
n-orbit coupling"\n
DTSTART;VALUE=DATE-TIME:20131016T150000Z
DTEND;VALUE=DATE-TIME:20131016T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13317@ictp.it
DESCRIPTION:We begin with a pedagogical introduction to the Physics of the
Mott Insulator to Superfluid transition (MI-SF)and its recent realization
in cold-atomic system. Then we elaborate on such MI-SF transition in sys
tems with two species of ultra-cold bosonic atoms in a two-dimensional squ
are optical lattice with nearest- neighbor hopping amplitude t and a spin-
orbit coupling k_SO. We chart out the phase diagram for the MI-SF transi
tion using both a strong-coupling expansion and Gutzwiller mean-field theo
ry. The momentum distribution near the MI-SF transition is shown to give p
recursor peaks. We analyze the critical theory of the transition revealing
the presence of unconventional quantum critical points at t/k_SO=0\, whic
h are accompanied by the emergence of an additional gapless mode in the cr
itical region. The Gutzwiller mean-field theory shows the existence of a
twisted superfluid phase. We study the distribution of phases and the magn
itude of the SF order parameter as a function of t and k_SO. We also study
the collective modes and the dynamics of the phases in the semi-classical
approach.\n\n//indico.ictp.it/event/a13317/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13317/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Quantum quench of t
he trap frequency in the harmonic Calogero model"
DTSTART;VALUE=DATE-TIME:20131022T100000Z
DTEND;VALUE=DATE-TIME:20131022T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13320@ictp.it
DESCRIPTION:We consider a quantum quench of the trap frequency in a system
of bosons interacting through an inverse-square potential and confined in
a harmonic trap (the harmonic Calogero model). We determine exactly the i
nitial state in terms of the post-quench eigenstates and derive the time e
volution of simple physical observables. Since this model possesses an inf
inite set of integrals of motion (IoM) that allow its exact solution\, a g
eneralised Gibbs ensemble (GGE)\, i.e. a statistical ensemble that takes i
nto account the conservation of all IoM\, can be proposed in order to desc
ribe the values of local physical observables long after the quench. Even
though\, due to the presence of the trap\, physical observables do not exh
ibit equilibration but periodic evolution\, such a GGE may still describe
correctly their time averaged values. We check this analytically for the l
ocal boson density and find that the GGE conjecture is indeed valid\, in t
he thermodynamic limit.\n\n//indico.ictp.it/event/a13320/
LOCATION:SISSA\, Santorio Building\, Room 5 (Ground floor)
URL://indico.ictp.it/event/a13320/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Chemical Physics: "Charge and exciton transfer
coupling in molecular materials"\n
DTSTART;VALUE=DATE-TIME:20131023T153000Z
DTEND;VALUE=DATE-TIME:20131023T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13321@ictp.it
DESCRIPTION:In modeling electronic and optical properties of molecular mat
erials it is of fundamental interest to estimate charge and exciton transf
er couplings between molecular sites. A short review of some quantum chemi
cal based approaches to evaluate such couplings will be presented\, focusi
ng especially on triplet exciton transfer as example.\n\n//indico.ictp.it/
event/a13321/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13321/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations\n"Quantum dyn
amics and topological phases of light in circuit-QED"
DTSTART;VALUE=DATE-TIME:20131024T103000Z
DTEND;VALUE=DATE-TIME:20131024T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13322@ictp.it
DESCRIPTION:Systems in cavity or circuit QED (Quantum Electrodynamics) are
extensively studied in the context of quantum information and quantum com
puting. In addition\, studying the non-equilibrium dynamics of photons in
these open quantum systems is a challenging theoretical question. Studying
“versatile lattice versions of these systems” open new doors to quan
tum simulation\, similar to ultra-cold atoms in optical lattices. In this
Talk\, we review our recent theoretical progress regarding (i) the develop
ment of methods to address the dynamics of driven and dissipative light-ma
tter systems beyond the weak-coupling limit and (ii) the realization of to
pological phases of light in superconducting QED-circuit arrays through sy
nthetic gauge fields. Effects of disorder will be studied. We also comment
on the current experimental status in circuit QED systems.\n\n//indico.ic
tp.it/event/a13322/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13322/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Quench dynamics in
interacting field-theories in one-dimension"\n
DTSTART;VALUE=DATE-TIME:20131028T130000Z
DTEND;VALUE=DATE-TIME:20131028T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13338@ictp.it
DESCRIPTION:Due to experiments in cold-atomic gases\, the study of quantum
quenches has become an active topic of research. While many rigorous res
ults exist for exactly solvable "free" theories\, not much is known about
the effect of non-linearities\, especially at long times and for systems i
n the thermodynamic limit\, where numerical studies are challenging. In t
his talk\, in order to highlight the main questions\, I will first present
results for a quench in an exactly solvable theory\, namely the Luttinger
model. I will then present results for the effect of various non-linearit
ies such as a commensurate periodic potential and a local back-scattering
potential.\nI will show that the dynamics following a quench can be quite
complex by being characterized by three regimes. One is a short time pertu
rbatively accessible regime which depends on microscopic parameters\, the
second is an intermediate time prethermalized regime where inelastic effec
ts are weak and correlation functions show universal scaling behavior whic
h is quantified by a nonequilibrium generalization of the Callan-Symanzik
equations. The third is a long time regime where inelastic effects become
important. For the case of the commensurate periodic potential\, I will sh
ow that these inelastic effects cause the system to eventually thermalize\
, where the thermalization time depends in a non-monotonic way on the quen
ch amplitude.\n\n//indico.ictp.it/event/a13338/
LOCATION: SISSA\, Santorio Building\, Room 129 (1st Floor)
URL://indico.ictp.it/event/a13338/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Statistical Physics: "Statistical mechanics of
multiplex networks"
DTSTART;VALUE=DATE-TIME:20131031T150000Z
DTEND;VALUE=DATE-TIME:20131031T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13336@ictp.it
DESCRIPTION:A large variety of complex systems\, from the brain to the wea
ther networks and complex infrastructures\, are formed by several networks
that coexist\, interact and coevolve forming a “network of networks”.
Modeling such multilayer structures and characterizing the rich interpla
y between their structure and their dynamical behavior is crucial in order
to understand and predict complex phenomena. In this talk I will present
recent works on statistical mechanics of multiplex networks. Multiplex ne
tworks are formed by N nodes linked in different layers by different netw
orks. I will present models that generate multiplexes with different types
of correlations between the layers\, and characterize new percolation phe
nomena on multiplex networks\, showing first order phase transitions\, b
istability or a complex phase diagram with tricriticals points and higher
order critical points.\n\n//indico.ictp.it/event/a13336/
LOCATION:ICTP Leonardo da Vinci Building Euler Lecture Hall
URL://indico.ictp.it/event/a13336/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Non-thermal
fixed points: Universality\, topology and turbulence in Bose systems"\n
DTSTART;VALUE=DATE-TIME:20131031T093000Z
DTEND;VALUE=DATE-TIME:20131031T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13339@ictp.it
DESCRIPTION:Among the wealth of possible non-equilibrium many-body configu
rations most interesting candidates are those which show universal behavio
r. New\, non-thermal fixed points are proposed\, leading beyond standard
equilibrium critical points. A selection of phenomena in ultracold Bose g
ases\, characterized by specific power-laws in space and time\, and univer
sal time evolution will be presented. These are\, for generic cases\, rel
ated to the presence and turbulent dynamics of (quasi-)topological defects
in the Bose field\, which are manifestly far from equilibrium. Examples
how to reach these critical points which will be discussed include interac
tion quenches and rapid evaporative cooling. Our results confirm non-pert
urbative quantum field theoretical predictions and establish a new link be
tween kinetic wave turbulence and topological excitations of superfluids.
They open a path to explore a new class of universal far-from-equilibrium
dynamics well accessible in ultracold gas experiments. These phenomena a
re of importance far beyond the realm of cold gases and allow a view on ne
w classifications of universal far-from-equilibrium physics.\n\n//indico.i
ctp.it/event/a13339/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13339/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Statistics of obser
vables and universal behaviour in quantum quenches and \ndynamical phase t
ransitions"\n
DTSTART;VALUE=DATE-TIME:20131105T103000Z
DTEND;VALUE=DATE-TIME:20131105T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13344@ictp.it
DESCRIPTION:The study of the dynamics of thermally isolated many-body syst
ems offers a unique opportunity to address the role of universality in non
equilibrium quantum phenomena. In this talk I will discuss recent results
concerning the statistics of the work and of other observables in spin cha
ins and bosonic systems out of equilibrium. I will show that the statistic
s of the work at low energies for spin chains (or bosonic systems) subject
to a generic local or global variation of the transverse field is indepen
dent on the detail of the protocol\, an example of universal behaviour bot
h in time and space. I will similarly show that the statistics of excitati
ons can be used to discuss universality and detect efficiently dynamical p
hase transitions.\n\n//indico.ictp.it/event/a13344/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13344/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Colloquium on Condensed Matter Physics: "The SU(N
) Heisenberg model of quantum permutations in condensed matter and cold at
oms"
DTSTART;VALUE=DATE-TIME:20131106T150000Z
DTEND;VALUE=DATE-TIME:20131106T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13343@ictp.it
DESCRIPTION:In this talk\, I will review the recent results we have obtain
ed on the SU(N) Heisenberg model of quantum permutations\, which describes
the low-energy properties of a number of Mott insulating phases in conden
sed matter physics (spin-1 antiferromagnets with biquadratic interaction\,
symmetric spin-orbital model) and cold atoms (ultracold ferminionic alkal
ine rare-earths in optical lattices). In 1D\, where Quantum Monte Carlo si
mulations can be performed\, we have calculated the correlations as a func
tion of the entropy per site\, with the conclusion that the entropy below
which characteristic features show up increases with N and reaches experim
entally accessible values already for N=4. \nIn 2D\, using a variety of an
alytical and numerical approaches\, in particular flavour-wave theory and
a tensor-network algorithm\, we have shown that the nature of the ground s
tate depends crucially on the value of N and on the topology of the lattic
e\, including long-range color order for SU(3) on the triangular and squar
e lattices\, spontaneous dimerization for SU(4) on the square lattice\, an
d an algebraic quantum liquid for SU(4) on the honeycomb lattice. Experime
ntal implications for condensed matter systems and cold atoms will be brie
fly discussed.\n\n//indico.ictp.it/event/a13343/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13343/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Fractional
topological insulators: A progress report"\n\n
DTSTART;VALUE=DATE-TIME:20131114T100000Z
DTEND;VALUE=DATE-TIME:20131114T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13353@ictp.it
DESCRIPTION:I will review the progress our group has made on the study of
topological insulators in the last year\, with an emphasis on some algebra
ic and geometric results.\n\n//indico.ictp.it/event/a13353/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13353/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Anderson model on t
he Bethe lattice\, new results on an old problem"\n
DTSTART;VALUE=DATE-TIME:20131119T103000Z
DTEND;VALUE=DATE-TIME:20131119T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13357@ictp.it
DESCRIPTION:I will discuss recent developments for the Anderson model on t
he Bethe lattice. In particular I will present evidence in favour of a non
-ergodic\, extended phase before the Anderson transition sets in.\n\n//ind
ico.ictp.it/event/a13357/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13357/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Chemical Physics: "Nanoscale structure\, surfa
ces and vacancies in sustainable energy materials: Interplay between exper
imental and ab-initio approaches"
DTSTART;VALUE=DATE-TIME:20131120T153000Z
DTEND;VALUE=DATE-TIME:20131120T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13355@ictp.it
DESCRIPTION:In this presentation\, our recent studies on future generation
thin film solar cells and hydrogen energy materials will be highlighted.
The presence of di-vacancies in hydrogenated amorphous silicon (a-Si:H) wa
s observed by a set of complementary techniques. These defects play an imp
ortant role in the instability of a-Si:H layers against light-soaking (Sta
ebler-Wronski effect). Further\, colloidal PbSe nanoparticles were investi
gated by positron annihilation spectroscopies and ab-initio calculations\,
shedding light on their surface composition and electronic structure. Fin
ally\, recent studies on the impact of nanoscale particle size\, surface e
nergies and the presence of vacancies on hydrogen storage materials and hy
drogen sensors are discussed.\n\n//indico.ictp.it/event/a13355/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13355/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Quantum flu
ids of light"\n
DTSTART;VALUE=DATE-TIME:20131121T103000Z
DTEND;VALUE=DATE-TIME:20131121T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13356@ictp.it
DESCRIPTION:A few years after the first observation of Bose-Einstein conde
nsation\, quantum gases of photons in suitably designed photonic microstru
ctures are establishing themselves as flexible and powerful platforms for
the study of many-body physics in a completely novel context.\nIn this tal
k\, I will start by reviewing the first experiments that have demonstrated
superfluid hydrodynamics effects in dilute photon fluids.\nWhen a localiz
ed defect is inserted in the flow\, a wide range of behaviors have been ob
served depending on the flow speed\, from superfluid flow to super-sonic M
ach cones\, to the nucleation of topological excitations such as solitons
and vortices.\nI will then proceed with the presentation of more recent wo
rk on synthetical gauge fields for photons and\, more generally\, geometri
cal and topological effects in quantum fluids of light in the presence of
periodic trapping potentials with different geometries.\nPerspectives towa
rds the generation of strongly correlated photon gases in the presence of
strong optical nonlinearities will be finally sketched\, with a special at
tention to quantum Hall liquids of light and the detection of their exotic
quasi-particle excitations.\n\n//indico.ictp.it/event/a13356/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13356/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Algebraic approach
to descendant form factors: Macdonald polynomials and null vectors"
DTSTART;VALUE=DATE-TIME:20131126T100000Z
DTEND;VALUE=DATE-TIME:20131126T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13361@ictp.it
DESCRIPTION:We give a short review of recent results (obtained together wi
th M. Lashkevich) on descendant form factors in sinh-Gordon and sine-Gordo
n models. We demonstrate that in algebraic approach one can find the equat
ions between the form factors of scaling fields which are analogous to nul
l vector equations of the correspondent CFT. In free field approach to CFT
the null vectors are related with Jack polynomials. We show that for pert
urbed massive case the story is very similar but null vector descendants a
re related with the Macdonald polynomials with the special parameters q=-t
and |q|=1. We briefly discuss the relation with the Deformed Virasoro Alg
ebra null vectors as well as some applications of the construction to deri
ving higher spins equations of motion and form factors of fields satisfyin
g a resonance condition.\n\n//indico.ictp.it/event/a13361/
LOCATION:SISSA\, Santorio Building\, Room 128 (1st Floor)
URL://indico.ictp.it/event/a13361/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Angular momentum bl
ockade in nanoscale high-Tc superconducting grains"\n
DTSTART;VALUE=DATE-TIME:20131203T100000Z
DTEND;VALUE=DATE-TIME:20131203T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13365@ictp.it
DESCRIPTION:The arise of an angular momentum blockade in small d-wave supe
rconducting grains embedded in external magnetic field is envisaged. It's
shown how abrupt changes in the angular momentum state of the condensate (
"angular momentum blockade") occur as a result of variation of the externa
l field. The effect represents a direct analogy with the Coulomb blockade.
A Ginzburg–Landau description is adopted to illustrate how a magnetic f
ield induces a deviation from the d-wave symmetry\, which is described by
a (d_{x2−y2} + id{xy})-order parameter. The volume magnetic susceptibili
ty will be described as a function of the magnetic field\, and correspondi
ng magnetization jumps\, that should be experimentally observable in super
conducting grains\, are predicted to occur near equispaced critical values
of the field.\n\n//indico.ictp.it/event/a13365/
LOCATION:SISSA\, Santorio Building\, Room 5 (Ground floor)
URL://indico.ictp.it/event/a13365/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations:\n"Moiré min
ibands in van der Waals heterostructures of graphene with hexagonal crysta
ls"\n
DTSTART;VALUE=DATE-TIME:20131205T103000Z
DTEND;VALUE=DATE-TIME:20131205T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13366@ictp.it
DESCRIPTION:The technological development of graphene has generated new hi
gh-quality systems offer access to the earlier inaccessible extremes of qu
antum physics. When graphene is placed on an atomically flat substrate wit
h hexagonal lattice with a close lattice constant\, such as boron nitride
(hBN)\, and their crystalline axes are aligned\, a long-wavelength perfect
ly periodic moiré pattern forms for electrons in graphene. In this talk\,
various regimes of possible moiré minibands at zero magnetic field [Phys
. Rev. B 87\, 245408 (2013)\; Phys. Rev. B 88\, 205418\; Phys. Rev. B 88\,
155415 (2013)] and strong magnetic field [Nature 497\, 594 (2013)\, arXiv
:1310.8578] will be discussed. Experimentally available magnetic fields ar
e enough to provide flux Phi through the moiré superlattice cell comparab
le to the magnetic flux quantum Phi_0 and reach the regime of fractal Hofs
tadter spectra. As a result\, a single device can offer a multiplicity of
two-dimensional electron systems\, realised at rational flux values Phi=
Phi_0\, = Phi_0/2\, 2= Phi_0/3\, etc.\, each with its own intricate topolo
gical properties\, including quantum Hall effect physics related to the ef
fective Landau levels emerging from these magnetic minibands at the nearby
range of magnetic fields.\n\n//indico.ictp.it/event/a13366/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13366/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Bringing quantum th
ermodynamics to the laboratory"\n
DTSTART;VALUE=DATE-TIME:20131210T103000Z
DTEND;VALUE=DATE-TIME:20131210T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13370@ictp.it
DESCRIPTION:Research on the out-of-equilibrium dynamics of quantum systems
has so far produced important statements on the thermodynamics of small s
ystems undergoing quantum mechanical evolutions. Key examples are provide
d by the Crooks and Jarzynski relations: taking into account fluctuations
in non-equilibrium dynamics\, such relations connect equilibrium propertie
s of thermodynamical relevance with explicit non-equilibrium features. Al
though the experimental verification of such fundamental relations in the
classical domain has encountered some success\, their quantum mechanical v
ersion requires the assessment of the statistics of work performed by or o
nto an evolving quantum system\, a step that has so far encountered consid
erable difficulties in its implementation due to the practical difficulty
to perform reliable projective measurements of instantaneous energy states
. In this talk I will outline a proposal [1] based on quantum phase estim
ation to extract quantum work statistics without the need to resort to pro
jective measurements. In addition I shall discuss an experimental collabo
ration which has successfully implemented the proposal in an NMR setting [
2]. I will also comment on some future extensions and directions on the th
eoretical side.\n\n[1] R. Dorner\, S.R. Clark\, L. Heaney\, R. Fazio\, J.
Goold\, and V. Vedral. Phys. Rev. Lett. 110 230601 (2013)\n\n[2] T. Bata
lhão\, A.M. Souza\, L. Mazzola\, R. Auccaise\, I.S. Oliveira\, J. Goold\,
G. De Chiara\, M. Paternostro\, R.M. Serra. arXiv.org:quant-ph/1308.3241v
1 (2013)\n\n//indico.ictp.it/event/a13370/
LOCATION:ICTP Leonardo da Vinci Building Luigi Stasi Seminar Room
URL://indico.ictp.it/event/a13370/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Functional renormal
ization group and a compactly supported smooth function"\n
DTSTART;VALUE=DATE-TIME:20131218T130000Z
DTEND;VALUE=DATE-TIME:20131218T190000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a13373@ictp.it
DESCRIPTION:Functional renormalization group (RG) method is suitable to pe
rform renormalization non-perturbatively. However\, the approximated RG eq
uations depend on the choice of the so called regulator function. Thus\,
optimisation is required in order to increase the predicting power of the
functional RG approach. As a result of a general optimisation strategy\,
the Litim-Pawlowski method\, one obtains Litim's regulator which is one of
the most frequently used regulator function. It is a continuous function
with a compact support but non-differentiable\, hence\, it confronts to t
he gradient expansion. Another optimization scenario is based on the Prin
ciple of Minimal Sensitivity which can be used at any order of the gradien
t expansion but regulators cannot be compared to each other. In my talk I
show how a compactly supported smooth regulator which reduces to all majo
r types of regulator functions in appropriate limits can solve these probl
ems.\n\n//indico.ictp.it/event/a13373/
LOCATION:SISSA\, Santorio Building\, Room 5 (Ground floor)
URL://indico.ictp.it/event/a13373/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Finite temperature
correlations in the 1D Lieb-Liniger Bose gas"\n
DTSTART;VALUE=DATE-TIME:20140114T103000Z
DTEND;VALUE=DATE-TIME:20140114T170000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14100@ictp.it
DESCRIPTION:We address the problem of calculating finite-temperature respo
nse functions of an experimentally relevant low-dimensional strongly-corre
lated system: the integrable 1D Bose gas with repulsive δ-function intera
ction (Lieb-Liniger model). Focusing on the dynamical density-density func
tion\, we present a Bethe Ansatz-based method allowing for its accurate ev
aluation in finite but large systems\, over broad ranges of momenta\, freq
uencies\, temperatures and interaction parameters which are difficult to a
ccess using other methods. This allows us to quantify the reshaping of the
zero temperature critical behavior by thermal fluctuations\, in experimen
tally accessible regimes.\n\n//indico.ictp.it/event/a14100/
LOCATION:ICTP
URL://indico.ictp.it/event/a14100/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Colloquium on Condensed Matter Physics: "Kinks an
d failure in isostatic networks"
DTSTART;VALUE=DATE-TIME:20140115T150000Z
DTEND;VALUE=DATE-TIME:20140115T170000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14101@ictp.it
DESCRIPTION:A minimal model for studying the mechanical properties of amor
phous solids is a disordered elastic network of point masses connected by
springs. At a critical (isostatic) value of its mean connectivity\, such a
network undergoes a rigidity transition signaled by vanishing elastic mod
uli and corresponding sound speed(s). We first investigate analytically an
d numerically the linear and non-linear visco-elastic response of these ne
arly isostatic networks by probing how shear fronts propagate through them
. \nOur approach\, that we tentatively label shear front rheology\, provid
es an alternative route to standard oscillatory rheology. In the linear re
gime\, we observe at late times a diffusive broadening of the fronts contr
olled by an effective shear viscosity that diverges at the critical point.
No matter how small the microscopic coefficient of dissipation\, strongly
disordered networks behave as if they were over-damped because energy is
irreversibly leaked into diverging non-affine fluctuations. Close to the t
ransition\, the regime of linear response becomes vanishingly small: the t
iniest shear strains generate strongly non-linear shear shock waves. The i
nherent non-linearities trigger an energy cascade from low to high frequen
cy components that keep the network away from attaining the quasi-static l
imit. This mechanism\, reminiscent of acoustic turbulence\, causes a super
-diffusive broadening of the shock width. \nFinally\, we show that the mec
hanism of failure of such networks\, consists of meandering cracks whose w
idth diverges at the transition. Thus\, upon approaching the critical poin
t\, we can effectively zoom inside the fracture process zone.\n\n//indico.
ictp.it/event/a14101/
LOCATION:ICTP
URL://indico.ictp.it/event/a14101/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "A functional RG equ
ation for the c-function"
DTSTART;VALUE=DATE-TIME:20140121T100000Z
DTEND;VALUE=DATE-TIME:20140121T170000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14111@ictp.it
DESCRIPTION:After showing how to prove the integrated c-theorem within the
functional RG framework based on the effective average action\, we derive
an exact RG flow equation for Zamolodchikov's c-function in two dimension
s by relating it to the flow of the effective average action. In order to
obtain a non-trivial flow for the c-function\, we will need to understand
the general form of the effective average action away from criticality\, w
here nonlocal invariants\, with beta functions as coefficients\, must be i
ncluded in the ansatz to be consistent. We then apply our construction to
several examples: exact results\, local potential approximation and loop e
xpansion. In each case we construct the relative approximate c-function an
d find it to be consistent with Zamolodchikov's c-theorem. Finally\, we pr
esent a relation between the c-function and the (matter induced) beta func
tion of Newton's constant\, allowing us to use heat kernel techniques to c
ompute the RG running of the c-function.\n\narXiv: 1312.7097\n\n//indico.i
ctp.it/event/a14111/
LOCATION:SISSA\, Santorio Building\, Room 005 (Ground floor)
URL://indico.ictp.it/event/a14111/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Old and New Results
on the Three Dimensional Ising Model"
DTSTART;VALUE=DATE-TIME:20140211T103000Z
DTEND;VALUE=DATE-TIME:20140211T170000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14134@ictp.it
DESCRIPTION:We discuss a few old results on the spectrum of the 3d Ising m
odel and on the behaviour of fluid interfaces in the low temperature phase
of the model which strongly disagree with the predictions of standard per
turbative calculations. Performing a duality transformation (i.e. mapping
the 3d Ising model into a Z_2 gauge theory) we show that these apparently
puzzling results are signatures of an underlying effective string descript
ion of the $Z_2$ gauge model. We then discuss a few recent advances which
drastically changed our understanding of these effective string theories a
nd allow to precisely fit both the interface free energy and the low tempe
rature spectrum of the Ising model.\n\n//indico.ictp.it/event/a14134/
LOCATION:ICTP
URL://indico.ictp.it/event/a14134/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Chemical Physics: "Non-radiative deactivation
mechanisms of electronically excited phenylalanine in model peptides"\n
DTSTART;VALUE=DATE-TIME:20140212T150000Z
DTEND;VALUE=DATE-TIME:20140212T170000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14135@ictp.it
DESCRIPTION:Studies of ultrafast non-radiative deactivation (NRD) mechanis
ms of electronically excited states of small model peptide systems in gas
phase\, such as N-acetylphenylalaninylamide (NAPA)\, can provide key insig
hts into the rich photochemistry of proteins\, especially the mechanisms r
esponsible for their photostability. We focus on elucidating the NRD pathw
ays of the vibrationless ππ* excited state in three NAPA conformers (βL
(a)\, γL(g+) and γL(g–)) and their conformer dependent excited state l
ifetime (70\, 1.5 and 35 ns\, respectively) as observed experimentally.1 P
otential NRD pathways were obtained from non-adiabatic molecular dynamics
simulations based on modified Tully’s fewest switch algorithm and on-the
-fly construction of potential energy surfaces and non-adiabatic couplings
using time dependent density functional theory.2 Two mechanisms exhibitin
g excitation transfer from the phenyl ππ* excited state to nπ* excited
states located on each amide group were further refined for all three conf
ormers. This includes the computation of the energy barriers and conical i
ntersection geometries on the coupled cluster (CC2) level of theory for th
e two mechanisms. By comparing the sizes of the vibrational zero point ene
rgy accessible part of the corresponding conical intersection seams\, as w
ell as the effects of methyl substitution on the primary amino group\, we
were able to pinpoint the specific mechanism responsible for the fast NRD
processes in the NAPA conformers. In a broader sense\, we disclose the str
uctural motifs/motions that control the relaxation dynamics in peptides an
d hence contribute to preventing their irreversible photochemical damage.3
\n\n1. M. Mališ\, Y. Loquais\, E. Gloaguen\, H. S. Biswal\, F. Piuzzi\,
B. Tardivel\, V. Brenner\, M. Broquier\, C. Jouvet\, M. Mons\, N. Došlić
\, I. Ljubić J. Am. Chem. Soc. 134 (2012) 20340 \n2. R. Mitrić\, U. Wern
er\, V. Bonačić-Kouteck. J. Chem. Phys. 129 (2008) 164118 \n3. M. Mališ
\, Y. Loquais\, E. Gloaguen\, C. Jouvet\, V. Brenner\, M. Mons\, I. Ljubi
ć\, N. Došlić Phys. Chem. Chem. Phys. 16 (2014) 2285\n\n//indico.ictp.i
t/event/a14135/
LOCATION:ICTP
URL://indico.ictp.it/event/a14135/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Many particle-physi
cs in one dimension: Correlations and dynamics"
DTSTART;VALUE=DATE-TIME:20140219T133000Z
DTEND;VALUE=DATE-TIME:20140219T170000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14140@ictp.it
DESCRIPTION:Abstract:\nThis seminar aims to give an introduction to the ph
ysics of strongly\ncorrelated fermions and bosons in one-dimension.\nI wil
l start from the description of the Tomonaga-Luttinger-Liquid (TLL)\nwhich
has been the cornerstone of our understanding of the properties of\none d
imensional systems. This universal set of properties plays in one\ndimensi
on\, the same role than Fermi liquid plays for the higher\ndimensional met
als. I will give an overview of some of the experimental\ntests that were
made to probe such TLL physics. In particular I will\ndetail some of the r
ecent experiments that were made in spin systems and\nwhich provided remar
kable quantitative tests of the TLL physics. Than I\nwill focus on bosons
in one-dimension and discuss their properties and\nthe effects of various
perturbations on the Tomonaga-Luttinger liquid\nstate\, as well as extens
ions to multicomponent and out of equilibrium\nsituations.\nThese extensio
ns are specially targeted for the experimental realizations\nthat have bee
n provided by cold atomic gases in optical lattices.\n\n//indico.ictp.it/e
vent/a14140/
LOCATION:SISSA\, Santorio Building\, Room 131 (first floor)
URL://indico.ictp.it/event/a14140/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA seminar in Statistical and Condensed Matter Physi
cs: "Non-equilibrium dynamics of strongly correlated cold atomic systems"\
n
DTSTART;VALUE=DATE-TIME:20140225T140000Z
DTEND;VALUE=DATE-TIME:20140225T170000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14142@ictp.it
DESCRIPTION:I will discuss few examples of out of equilibrium dynamics of
trapped atomic systems. I will first consider the breathing mode of an im
purity coupled to a bath of interacting bosons. I will then proceed analyz
ing topological pumping in the extended Bose-Hubbard model. If time allow
s I will briefly analyse the dynamics of colliding spin-polarized fermion
clouds.\n\n//indico.ictp.it/event/a14142/
LOCATION:ICTP
URL://indico.ictp.it/event/a14142/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Universal Behavior
of Shannon and Renyi Mutual Information of Quantum Spin Chains"
DTSTART;VALUE=DATE-TIME:20140306T103000Z
DTEND;VALUE=DATE-TIME:20140306T170000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14147@ictp.it
DESCRIPTION:In this talk we will first review the Shannon and Renyi entrop
ies as\ninformation theoretic concepts and their use in quantum and classi
cal\nsystems. They are quantities which usually base dependent. Then we w
ill\nintroduce mutual Shannon and mutual Renyi entropies as very useful\nq
uantities to detect the universality classes of the quantum spin chains. W
e\nwill present some conjectures regarding the connection of these quantit
ies\nto central charge of the critical systems and then we will support th
em with\nnumerical works done on the Ising model Q=3\,4 Potts model and XX
Z spin chains.\nIn all of these cases we will emphasize on the bases that
one\nchooses to calculate these quantities and in particular we will show
that\nsome of the bases are actually more suitable to detect the universal
ity\nclasses.\n\nReferences:\n1: FC Alcaraz\, MA Rajabpour\, Phys. Rev. Le
tt. 111\, 017201 (2013)\n2: FC Alcaraz\, MA Rajabpour\, in preparation.\n\
n//indico.ictp.it/event/a14147/
LOCATION:ICTP
URL://indico.ictp.it/event/a14147/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Universal quantum s
imulator\, local convertibility and edge states in many-body systems"
DTSTART;VALUE=DATE-TIME:20140311T100000Z
DTEND;VALUE=DATE-TIME:20140311T170000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14155@ictp.it
DESCRIPTION:In some many-body systems\, certain ground state entanglement
(Renyi) entropies increase even as the correlation length decreases. This
entanglement non-monotonicity implies a stronger "quantum nature" of the w
ave function and gives it a higher computational power\, compared to class
ical manipulations. We will demonstrate that such a phenomenon\, known as
non-local convertibility\, is due to the edge state (de)construction occur
ring in the system. To this end\, we employ the example of the Ising chain
\, displaying an order-disorder quantum phase transitions. Employing both
analytical and numerical methods\, we compute entanglement entropies for
various system's bipartitions (A|B) and consider ground states with and wi
thout Majorana edge states. We find that the thermal ground states\, enjo
ying the Hamiltonian symmetries\, show non-local convertibility if either
A or B are smaller than\, or of the order of\, the correlation length. In
contrast\, the ordered (symmetry breaking) ground state is always locally
convertible. The edge states behavior explains all these results and could
disclose a paradigm to understand local convertibility in other quantum p
hases of matter. The connection we establish between convertibility and no
n-local\, quantum correlations provides a clear criterion of which feature
s a universal quantum simulator should possess to outperform a classical m
achine.\n\nReferences:\n- Fabio Franchini\, Jian Cui\, Luigi Amico\, Heng
Fan\, Mile Gu\, Vladimir E. Korepin\, Leong Chuan Kwek\, Vlatko Vedral.
http://arxiv.org/abs/1306.6685\n\n//indico.ictp.it/event/a14155/
LOCATION:SISSA\, Santorio Building\, Room 128 (First floor)
URL://indico.ictp.it/event/a14155/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Precision Measureme
nts of Temperature and Chemical Potential of Quantum Gases"
DTSTART;VALUE=DATE-TIME:20140313T103000Z
DTEND;VALUE=DATE-TIME:20140313T170000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14159@ictp.it
DESCRIPTION:We investigate the sensitivity with which the temperature and
the chemical potential characterizing quantum gases can be measured. We ca
lculate the corresponding quantum Fisher information matrices for both fer
mionic and bosonic gases. For the latter\, particular attention is devoted
to the situation close to the Bose-Einstein condensation transition\, whi
ch we examine not only for the standard scenario in three dimensions\, but
also for generalized condensation in lower dimensions\, where the bosons
condense in a subspace of Hilbert space instead of a unique ground state\,
as well as condensation at fixed volume or fixed pressure. We show that B
ose Einstein condensation can lead to sub-shot noise sensitivity for the m
easurement of the chemical potential. We also examine the influence of int
eractions on the sensitivity in three different models\, and show that mea
n-field and contact interactions deteriorate the sensitivity but only slig
htly for experimentally accessible weak interactions.\n\n//indico.ictp.it/
event/a14159/
LOCATION:ICTP
URL://indico.ictp.it/event/a14159/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Charge tran
sport: The rise of the helical modes"
DTSTART;VALUE=DATE-TIME:20140327T103000Z
DTEND;VALUE=DATE-TIME:20140327T170000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14163@ictp.it
DESCRIPTION:Helical modes\, in which the momentum and spin quantum numbers
are strongly coupled\, have recently appeared in the front line of one-di
mensional physics through the discovery of materials exhibiting the quantu
m spin-Hall effect. The fascinating conduction properties of the edge stat
es of such materials is determined not just by the naturally strongly corr
elated nature of one-dimensional quantum systems\, but also through the he
lical nature of such modes.\n\nIn this presentation\, I will consider two
examples of helical modes. The first arises in the edge states of the qua
ntum spin-Hall effect\, where I will consider how the helical structure of
the states influences the Kondo effect when one traps a single spin withi
n a double constriction. The second example appears when domain walls are
induced into the quantum Hall state of bilayer graphene under appropriate
gating. I will demonstrate that one-dimensional helical modes form on th
is kink\, which may then be tuned through a quantum phase transition in th
e Z_2 universality class. The helical nature of the modes means the two p
hases on either side of this transition have distinct conducting propertie
s\, in particular one is superfluid and the other is insulating.\n\nRefere
nces:\n\nC.-W. Huang\, S.T. Carr\, D. Gutman\, E. Shimshoni and A.D. Mirl
in\, PRB 88\, 125134 (2013)\nV. Mazo\, C.-W. Huang\, E. Shimshoni\, S.T. C
arr and H.A. Fertig\, arXiv:1309.1563\n\n//indico.ictp.it/event/a14163/
LOCATION:ICTP
URL://indico.ictp.it/event/a14163/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Giant magne
todrag in graphene at charge neutrality"\n
DTSTART;VALUE=DATE-TIME:20140403T103000Z
DTEND;VALUE=DATE-TIME:20140403T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14165@ictp.it
DESCRIPTION:We report experimental data and theoretical analysis of Coulom
b drag between two closely positioned graphene monolayers in a weak magnet
ic field. Close enough to the neutrality point\, the coexistence of elect
rons and holes in each layer leads to a dramatic increase of the drag resi
stivity. Away from charge neutrality\, we observe nonzero Hall drag. The
observed phenomena are explained by decoupling of electric and quasiparti
cle currents which are orthogonal at charge neutrality. The sign of magne
todrag depends on the energy relaxation rate and geometry of the sample.\n
\n//indico.ictp.it/event/a14165/
LOCATION:ICTP
URL://indico.ictp.it/event/a14165/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Single Molecules: F
rom Force Spectroscopy to Molecular Evolution"
DTSTART;VALUE=DATE-TIME:20140403T130000Z
DTEND;VALUE=DATE-TIME:20140403T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14167@ictp.it
DESCRIPTION://indico.ictp.it/event/a14167/
LOCATION:SISSA\, Santorio Building\, Room 128 (first floor)
URL://indico.ictp.it/event/a14167/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar: " From metadynamics to dynamics "
DTSTART;VALUE=DATE-TIME:20140505T103000Z
DTEND;VALUE=DATE-TIME:20140505T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14188@ictp.it
DESCRIPTION:Metadynamics is a commonly used and successful enhanced sampli
ng method. By the introduction of a history dependent bias which depends
on a restricted number of collective variables it can explore complex free
energy surfaces characterized by several metastable states separated by l
arge free energy barriers. We recently extended its scope by introducing
a simple yet powerful method for calculating the rates of transition betwe
en different metastable states. The method does not rely on a previous kn
owledge of the transition states or reaction coordinates\, as long as coll
ective variables are known that can distinguish between the various stable
minima in free energy space. A statistical analysis of the distribution
of transition times allows us to verify a posteriori the reliability of ou
r calculations\, and if any relevant slow collective variables are missing
. We apply our method to a number of examples of increasing complexity.
We find excellent agreement between our calculations and the results of lo
ng unbiased molecular dynamics simulations whenever the latter are feasibl
e.\n\nReferences\n1. P. Tiwary and M. Parrinello\, Phys. Rev. Lett. 111 (2
30602)\, 2013.\n2. M. Salvalaglio\, P. Tiwary and M. Parrinello\, J. Chem.
Theor.& Comp. (in press)\, 2014.\n\n//indico.ictp.it/event/a14188/
LOCATION:ICTP
URL://indico.ictp.it/event/a14188/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: Conformal Invariance
of Critical Fluctuations in d=3
DTSTART;VALUE=DATE-TIME:20140506T100000Z
DTEND;VALUE=DATE-TIME:20140506T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14189@ictp.it
DESCRIPTION:Abstract:\nIt has been conjectured in 1971 by Polyakov that cr
itical phenomena\nhave conformal invariance\, both in two and three dimens
ions. While the\ntwo dimensional case has been intensely studied\, the rol
e of conformal\ninvariance in d=3 is not fully clarified. We will describe
which parts\nof conformal field theory carry over from d=2 to d=3. We wil
l describe\nthe `conformal bootstrap' equations\, whose solutions should g
ive\nconformally invariant algebras of local operators in d=3. The simples
t\ncase is the operator algebra corresponding to the critical point of\nth
e 3d Ising model. We conjecture that this operator algebra can be\ncharact
erized by a minimal central charge condition. Numerical\nevidence for this
conjecture will be presented. (based on\narxiv:1403.4545).\n\n//indico.ic
tp.it/event/a14189/
LOCATION:SISSA\, Santorio Building\, Room 005
URL://indico.ictp.it/event/a14189/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar on Disorder and strong electron correlations: "Fluctuation
-induced first-order quantum phase transition of the U(1) spin liquid in a
pyrochlore quantum spin ice"\n\n
DTSTART;VALUE=DATE-TIME:20140522T103000Z
DTEND;VALUE=DATE-TIME:20140522T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14198@ictp.it
DESCRIPTION:We predict\, using a free-energy calculation\, that the quantu
m phase transition between the U(1) quantum spin liquid (QSL) and antiferr
omagnet (AFM) phases in certain pyrochlore quantum spin ice is first order
rather than second order. This change in order from second to first orde
r is induced by gauge fluctuations\, which are explicitly taken into accou
nt at gauge theory level in our effective low-energy theory. We therefore
have identified a fluctuation-induced first-order quantum phase transitio
n in pyrochlore quantum spin ice. We explicitly derive the quantum free-e
nergy description of this QSL-to-AFM phase transition and predict that it
is a weakly first-order phase transition. We also briefly discuss the exp
erimental relevance of this result.\n\n//indico.ictp.it/event/a14198/
LOCATION:ICTP
URL://indico.ictp.it/event/a14198/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special Lecture in Statistical Physics of Complex Systems: "Algori
thms for Computational Social Science"
DTSTART;VALUE=DATE-TIME:20140529T150000Z
DTEND;VALUE=DATE-TIME:20140529T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14201@ictp.it
DESCRIPTION:Abstract: \nThe availability of large datasets has allowed sci
entists to probe the dynamics of social systems to unprecedented levels of
details. We will provide a general overview of the main problems and give
a few specific examples in three fields\, namely:\na) Language Dynamics \
nb) Community Detection \nc) Citation Analysis\n\n//indico.ictp.it/event/a
14201/
LOCATION:ICTP
URL://indico.ictp.it/event/a14201/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA INFORMAL SEMINAR on Statistical Physics: "Space U
se by Foragers with Renewable Resources"
DTSTART;VALUE=DATE-TIME:20140529T130000Z
DTEND;VALUE=DATE-TIME:20140529T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14202@ictp.it
DESCRIPTION:Abstract:\nWe are participating in a project to study and unde
rstand a keystone mutualistic system in the Patagonian temperate forest. I
t is composed of two specialist partners: a small arboreal marsupial that
feeds on the fruits of a hemiparasite shrub and disperses it seeds. As par
t of this effort we have described the movement of the animals in a hetero
geneous landscape as a walk that dynamically affects its substrate.\n\nOur
simplest model provides an insight on a number of relevant and non-intuit
ive facts. Even without memory of the good places to feed and no explicit
cost of moving\, we observe the emergence of a finite home range. The reas
on for this is that memory of the usage of the landscape is kept in the la
ndscape itself. The arising paths looks surprisingly similar to real anima
l tracks. We characterize this walks and their use of the resources in sev
eral statistical ways. Preliminary results on population effects are explo
red by means of a system of two non (directly) interacting animals.\n\nThi
s work is a first step towards a complex model that will take into conside
ration the interaction between plants and seed dispersers and the synergis
tic effect that arises from their mutualistic interaction. Despite its ins
piration on a very specific system\, this first step is of very general ap
plication and may be of interest in other contexts.\n\n//indico.ictp.it/ev
ent/a14202/
LOCATION:ICTP
URL://indico.ictp.it/event/a14202/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Chemical Physics: "Ensemble approaches to the
computer simulation of site-disordered solids"\n
DTSTART;VALUE=DATE-TIME:20140604T103000Z
DTEND;VALUE=DATE-TIME:20140604T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14203@ictp.it
DESCRIPTION:Site-occupancy disorder\, defined as the non-periodic occupati
on of lattice sites in a crystal structure\, is a ubiquitous phenomenon in
solid-state physics and chemistry. Examples are mineral solid solutions\,
synthetic non-stoichiometric compounds and metal alloys. The experimental
investigation of these materials using diffraction techniques only provid
es averaged information of their structure. However\, many properties of i
nterest in these solids are determined by the local geometry and degree of
disorder\, which escape an “average crystal” description\, either fro
m experiments or from theory. In this talk\, I will introduce a methodolo
gy for the computer simulation of site-disordered solids\, based on the co
nsideration of configurational ensembles and statistical mechanics [1\, 2]
. The number of occupancy configurations is reduced by taking advantage of
the crystal symmetry of the lattice. Thermodynamics and non-thermodynamic
properties are then defined from the statistics in the symmetry-adapted c
onfigurational ensemble. I will briefly discuss some recent applications o
f this methodology and of its generalization to grand-canonical ensembles
[3-7]. \n\n1. R. Grau-Crespo\, S. Hamad\, et al.\, Symmetry-adapted config
urational modelling of fractional site occupancy in solids. Journal of Phy
sics-Condensed Matter\, 2007. 19: 256201.\n2. R. Grau-Crespo and U. V. Wag
hmare. Simulation of crystals with chemical disorder at lattice sites. In
Molecular Modeling for the Design of Novel Performance Chemicals and Mater
ials. Edited by Beena Rai. CRC Press Inc. ISBN 9781439840788 (2012).\n3. R
. Grau-Crespo\, K. C. Smith\, et al.\, Thermodynamics of hydrogen vacancie
s in MgH2 from first-principles calculations and grand-canonical statistic
al mechanics. Physical Review B\, 2009. 80: 174117 \n4. K. C. Smith\, T. S
. Fisher\, U.V. Waghmare\, R. Grau-Crespo\, Dopant-vacancy binding effects
in Li-doped magnesium hydride. Physical Review B\, 2010. 82: 134109.\n5.
R. Grau-Crespo\, N. H. De Leeuw\, et al.\, Phase separation and surface se
gregation in ceria-zirconia solid solutions. Proceedings of the Royal Soci
ety A-Mathematical Physical and Engineering Sciences\, 2011. 467: 1925-193
8.\n6. S. E. Ruiz-Hernandez\, R. Grau-Crespo\, et al.\, Mg/Ca partitioning
between aqueous solution and aragonite mineral: a molecular dynamics stud
y. Chemistry - A European Journal\, 2012. 18: 9828-9833.\n7. P. Rivero\, I
.D.P.R. Moreira\, R. Grau-Crespo\, S. N. Datta\, F. Illas. General model f
or explicitly hole-doped superconductor parent compounds: Electronic struc
ture of Ca2-xNaxCuO2Cl2 as a case study. Physical Review B\, 2013. 88\, 0
85108.\n\n//indico.ictp.it/event/a14203/
LOCATION:ICTP
URL://indico.ictp.it/event/a14203/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Anderson Localizati
on on the Bethe Lattice: Non-ergodicity of Extended States"
DTSTART;VALUE=DATE-TIME:20140613T100000Z
DTEND;VALUE=DATE-TIME:20140613T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14212@ictp.it
DESCRIPTION://indico.ictp.it/event/a14212/
LOCATION:SISSA\, Santorio Building\, Room 131 (first floor)
URL://indico.ictp.it/event/a14212/
END:VEVENT
BEGIN:VEVENT
SUMMARY:QUANTITATIVE BIOLOGY SEMINAR: "Gyrotactic Phytoplankton Swimming i
n a Flow"
DTSTART;VALUE=DATE-TIME:20140708T130000Z
DTEND;VALUE=DATE-TIME:20140708T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14217@ictp.it
DESCRIPTION:Many aquatic microorganisms are able to swim and typically do
it in a moving\, sometimes turbulent\, fluid environment. The interaction
between swimming (self-propulsion) and flow advection can give rise to int
eresting phenomenology\, especially concerning the spatial distribution of
microbes. Many aspects of such interaction can be understood by using ide
as and tools from dynamical systems theory and fluid mechanics. Here we sh
all discuss some of these aspects focusing on the case study of gyrotactic
phytoplankton\, which swims by means of two flagella opposite to the cent
er of mass\, which is displaced with respect to the center of symmetry ---
bottom heavy cells.\n\n//indico.ictp.it/event/a14217/
LOCATION:ICTP
URL://indico.ictp.it/event/a14217/
END:VEVENT
BEGIN:VEVENT
SUMMARY:QUANTITATIVE BIOLOGY SEMINAR: "Simple Behavior of Complex Biologic
al Networks"
DTSTART;VALUE=DATE-TIME:20140710T150000Z
DTEND;VALUE=DATE-TIME:20140710T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14220@ictp.it
DESCRIPTION:Recent high-precision and high-throughput measurements of biol
ogical networks dynamics have uncovered interesting results. Namely\, many
biological systems appear to be critical (so that their dynamics can be c
lassified into a handful of universal classes)\, or are described with hig
h accuracy by surprisingly simple\, phenomenological models. I will explor
e a handful of simple theoretical models inspired by these observations\,
suggesting plausible explanations for this emergence of coarse-grained sim
plicity from complex microscopic structures.\n\n//indico.ictp.it/event/a14
220/
LOCATION:ICTP
URL://indico.ictp.it/event/a14220/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Quantum Quenches in
the XXZ Spin Chain and the Generalized Gibbs Ensemble"
DTSTART;VALUE=DATE-TIME:20140710T100000Z
DTEND;VALUE=DATE-TIME:20140710T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14225@ictp.it
DESCRIPTION:Isolated integrable quantum systems do not relax to a thermal
state even locally due to the extra conserved quantities that they possess
. The so-called Generalized Gibbs Ensemble (GGE) was proposed to capture t
he steady state of integrable systems\, but it has not been put to a strin
gent test for genuinely interacting systems.\nIn the talk I will review ou
r work on the non-equilibrium time evolution of the spin-1/2 anisotropic H
eisenberg (XXZ) spin chain\, where we found that short-ranged spin correla
tors in the long-time limit deviate significantly from predictions based o
n the GGE hypothesis. By computing the asymptotic spin correlators within
the quench action formalism based on exact overlaps\, however\, we find ex
cellent agreement with the numerical data. I will show why this result can
be considered as conclusive evidence for the failure of the GGE and I wil
l discuss the possible implications of this finding.\n\n//indico.ictp.it/e
vent/a14225/
LOCATION:SISSA\, Santorio Building\, Room 138
URL://indico.ictp.it/event/a14225/
END:VEVENT
BEGIN:VEVENT
SUMMARY:QUANTITATIVE BIOLOGY SEMINAR: "Fluxes\, Scaling and Dimensions in
Fully Developed Turbulence"
DTSTART;VALUE=DATE-TIME:20140715T153000Z
DTEND;VALUE=DATE-TIME:20140715T180000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14221@ictp.it
DESCRIPTION:In this seminar\, I will discuss a few important open problems
in 'Fully Developed Turbulence' concerning its most idealised realisation
\, i.e. the case of statistically homogeneous and isotropic flows. I will
discuss the importance of inviscid conserved quantities in relation to the
most striking statistical properties shown by all turbulent flows: the gr
owth of small-scale strongly non-Gaussian fluctuations\, including the pre
sence of anomalous scaling laws.Â By using unconventional numerical meth
odology\, based on aÂ GalerkinÂ decimation of helical Fourier modes\, I
will argue that some phenomena characterising homogeneous and isotropic fl
ows might be important also for a much larger spectrum of applications\, i
ncluding flows with geophysical and astrophysical relevance as for the cas
e of rotating turbulence and/or conducting fluids.\n\n//indico.ictp.it/eve
nt/a14221/
LOCATION:ICTP
URL://indico.ictp.it/event/a14221/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "New Results for Qua
ntum Antiferromagnets in High Magnetic Fields"
DTSTART;VALUE=DATE-TIME:20140721T150000Z
DTEND;VALUE=DATE-TIME:20140721T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14226@ictp.it
DESCRIPTION:Frustrated antiferromagnets are a very rich class of physical
systems\, in which various new phases of matter are expected to be realize
d. From a theoretical point of view\, however\, they present challenging d
ifficulties and typically defy a full quantum treatment. A possible strate
gy is to restrict oneself to a specific region of the parameter space\, na
mely the one of high applied magnetic field\, where the problem can be map
ped to a dilute Bose gas of magnons. In this way we can provide benchmarks
for the latest numerical approaches\, such as in the case of the prototyp
ical spin-1/2 XXZ model on the triangular lattice [1]. In more complicated
models with competing exchange interactions\, we find new types of magnet
ic order\, such as a double-q state with striped chiral order [2]. Several
problems remain open in this field-theoretical approach\, in particular t
hree-magnon and four-magnon scattering amplitudes\, which relate to a rece
ntly discovered magnetic "0-pi" phase transition and to the stability of t
he spin nematic phase respectively.\n\n[1] D. Yamamoto\, G. Marmorini and
I. Danshita\, Phys. Rev. Lett. 112\n(2014) 127203.\n[2] G. Marmorini and T
. Momoi\, Phys. Rev. B 89\, 134425 (2014).\n\n//indico.ictp.it/event/a1422
6/
LOCATION:ICTP
URL://indico.ictp.it/event/a14226/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Statistical Physics "Evolution of sex and reco
mbination"\n
DTSTART;VALUE=DATE-TIME:20140821T103000Z
DTEND;VALUE=DATE-TIME:20140821T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14326@ictp.it
DESCRIPTION:I will introduce and discuss some basic population genetic mod
els that have been studied to understand the evolution of sex and recombin
ation. After explaining the known results\, I will describe some open prob
lems in the subject.\n\n//indico.ictp.it/event/a14326/
LOCATION:ICTP
URL://indico.ictp.it/event/a14326/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on: "Nanoscience in Costa Rica and Computational
study of Pakhomovskyite electronic and magnetic properties"
DTSTART;VALUE=DATE-TIME:20140827T103000Z
DTEND;VALUE=DATE-TIME:20140827T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14328@ictp.it
DESCRIPTION:In this talk I'm going to present some of the experiments and
projects that are currently active at the Universidad de Costa Rica in the
area of nanoscience. In particular I'm going to mention some projects wh
ere the support of DFT and MD calculations will have a relevant impact in
the interpretation and comprehension of present experimental results.\n\nI
n the second part\, I'm going to focus on a specific project: "Ca-Co phosp
hates as catalysts in water electrolysis". This project aims to study the
catalytic properties of Pakhomovskyite.\n\nPakhomovskyite is a vivianite
structure with layers of cobalt phosphate structures that are joined toget
her by hydrogen bonds. This structure has been proposed for various cobalt
based catalysts. The main advantage is that the structure can sustain ch
anges in oxidation state while the same structure remains. The experiment
al results lead to important questions in water splitting catalysis. Never
theless\, none theoretical work has been done in this material. Therefore
\, in the present project we aim to use DFT calculations in order to study
its magnetic and electronic properties\, allowing us to select the best c
andidates to be synthesized later by the experimental group.\n\n//indico.i
ctp.it/event/a14328/
LOCATION:ICTP
URL://indico.ictp.it/event/a14328/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal Seminar on Statistical Physics: "Extreme Events in Physic
al Systems and Complex Networks"
DTSTART;VALUE=DATE-TIME:20140911T103000Z
DTEND;VALUE=DATE-TIME:20140911T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14335@ictp.it
DESCRIPTION:Extreme events such as cyclones\, earthquakes\, power blackout
s or traffic jams are not uncommon.\nStudy of such events using the framew
ork of extreme value theory has a long history. In this talk\, we will int
roduce the idea of extreme events and review some of the recent results. \
nIn the second half\, we will discuss transport processes based on random
walks and associated extreme events taking place on complex networks. We s
how that extreme events on complex networks are more likely to take place
on small degree nodes and not on the hubs.\nWe will discuss some generalis
ations and applications of these results.\n\n//indico.ictp.it/event/a14335
/
LOCATION:ICTP
URL://indico.ictp.it/event/a14335/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Kondo Physics from
a Quantum Information Perspective"
DTSTART;VALUE=DATE-TIME:20140912T090000Z
DTEND;VALUE=DATE-TIME:20140912T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14336@ictp.it
DESCRIPTION:A characterization of a Kondo system using only entanglement m
easures is provided. For this purpose: I shall firstly analyze a spin real
ization of the single channel Kondo model and show how one can determine t
he Kondo screening length by a measure of entanglement. I then show how th
e entanglement with the impurity “stored” in the Kondo cloud may be us
ed to generate distance independent long range entanglement between the en
d point of a Kondo spin chain.\n\n//indico.ictp.it/event/a14336/
LOCATION:SISSA\, Santorio Building\, Room 5
URL://indico.ictp.it/event/a14336/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Low energy electron
-phonon effective action from symmetry analysis"
DTSTART;VALUE=DATE-TIME:20140930T090000Z
DTEND;VALUE=DATE-TIME:20140930T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-a14347@ictp.it
DESCRIPTION:In this talk\, based on a detailed symmetry analysis\, I will
state the general rules to build up the effective low energy field theory
describing a system of electrons weakly interacting with the lattice degre
es of freedom. The basic elements in the construction are the invariant te
nsors that keep track of the microscopic discrete symmetries into the coar
se-grained action. The approach can be applied to lattice systems in arbit
rary dimensions and in a systematic way to any desired order in derivative
s. I will show the application of the method to the honeycomb lattice and
re-obtain the well-known effective action for graphene\, containing Dirac
fermions coupled to a fictitious gauge field. The talk is based on the res
ults of arXiv:1303.3442\n\n//indico.ictp.it/event/a14347/
LOCATION:SISSA\, Santorio Building\, Room 138 (first floor)
URL://indico.ictp.it/event/a14347/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Universal Dynamics
Near and Far from Equilibrium"
DTSTART;VALUE=DATE-TIME:20141010T123000Z
DTEND;VALUE=DATE-TIME:20141010T133000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7285@ictp.it
DESCRIPTION:Abstract:\n\n The quantitative understanding of universal dyna
mic properties of strongly correlated systems both near and far from equi
librium poses one of the most diverse and challenging problems in contempo
rary physics. Applications cover a huge range of scales\, from low temper
ature states of condensed matter systems to the extreme states of matter
observed\, e.g.\, in ultra-relativistic heavy-ion collisions. Functional m
ethods\, e.g.\, the functional renormalization group and effective action
techniques\, as well as numerical lattice Monte Carlo methods offer a pow
erful approach to tackle these problems and to resolve the nonperturbativ
e dynamics. Here\, I focus on their applications to critical dynamics in
stochastic models with energy conservation as well as universal scaling ph
enomena in hydrodynamic systems driven far from equilibrium.\n\n//indico.
ictp.it/event/7285/
LOCATION:SISSA Cinema Room
URL://indico.ictp.it/event/7285/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: "Interaction Quench
in One-dimensional Bose Gas"
DTSTART;VALUE=DATE-TIME:20141014T090000Z
DTEND;VALUE=DATE-TIME:20141014T100000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7286@ictp.it
DESCRIPTION:\n Abstract: We consider the quench of the one-dimensional Bos
e gas from zero to infinite interaction\, in which the relation between mo
des is nonlinear\, and consequently Wick's theorem does not hold. We provi
de exact analytical results for the time evolution of the dynamical densit
y-density correlation function. We prove that its stationary value is desc
ribed by a Generalized Gibbs Ensemble (GGE). Finally\, we analyze the enta
nglement properties of the the asymptotic steady state after the quench\;
we provide exact analytical results both for the leading extensive parts a
nd the subleading terms for the entropies as well as for the cumulants of
the particle number fluctuations.\n\n//indico.ictp.it/event/7286/
LOCATION:SISSA "Cinema Room"
URL://indico.ictp.it/event/7286/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics Seminar: Topological Phases i
n Ultracold Fermionic Gases
DTSTART;VALUE=DATE-TIME:20141021T120000Z
DTEND;VALUE=DATE-TIME:20141021T130000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7296@ictp.it
DESCRIPTION:The experimental simulation of gauge potentials and spin-orbit
couplings in ultracold atomic gases paves the way to realize intriguing t
opological phases in these physical setups. In this talk I will describe h
ow the interplay between synthetic magnetic fields and spin-orbit coupling
s allows to simulate topological insulators in optical lattices. I will an
alyse some example of topological phase transitions in these systems and I
will examine possible experimental signatures of the non-trivial topologi
cal phases.\n\n//indico.ictp.it/event/7296/
LOCATION:SISSA\, Cinema Room
URL://indico.ictp.it/event/7296/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: Inverse problems for
spreading dynamics on networks.
DTSTART;VALUE=DATE-TIME:20141104T100000Z
DTEND;VALUE=DATE-TIME:20141104T111500Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7304@ictp.it
DESCRIPTION:Who are the most influential players in a social network? What
's the origin of an epidemic outbreak? The answer to simple questions like
these can hide incredibly difficult computational problems\, that require
powerful methods for the inference\, optimization\, and control of dynami
cal processes on large networks.\nI will present a statistical mechanics a
pproach to inverse dynamical problems in the idealized framework provided
by simple models of irreversible contagion and diffusion on networks (line
ar threshold model\, susceptible-infected-removed epidemic model). Using t
he cavity method (belief propagation)\, it is possible to explore the larg
e-deviation properties of the dynamics and develop efficient message-passi
ng algorithms to solve optimization and inference problems even on large n
etworks.\n\n//indico.ictp.it/event/7304/
LOCATION:SISSA Cinema Room - 1st floor
URL://indico.ictp.it/event/7304/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Eigenstate thermali
zation hypothesis (ETH) and integrability in quantum spin chains"
DTSTART;VALUE=DATE-TIME:20141111T100000Z
DTEND;VALUE=DATE-TIME:20141111T110000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7310@ictp.it
DESCRIPTION:ABSTRACT\nWe investigate the eigenstate thermalization hypothe
sis (ETH) in integrable models\, focusing on the spin-1/2 isotropic Heisen
berg (XXX) chain. We verify that ETH holds for typical eigenstates (weak
ETH scenario). Specifically\, using a numerical implementation of state
-of-the-art Bethe ansatz results\, we study the finite-size scaling of the
eigenstate-to-eigenstate fluctuations of the reduced density matrix. Fl
uctuations are normally distributed\, and their standard deviation decays
in the thermodynamic limit as L^{-1/2}\, with L the size of the chain. T
his is in contrast with the exponential decay that is found in generic non
-integrable systems. Finally\, we investigate the entanglement propertie
s of the excited states of the XXX chain. We numerically verify that typ
ical mid-spectrum eigenstates exhibit extensive entanglement entropy (i.e.
\, volume-law scaling).\n\n//indico.ictp.it/event/7310/
LOCATION:SISSA\, Santorio Building Cinema Room\, 1st floor
URL://indico.ictp.it/event/7310/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Glimmers of a quant
um KAM theorem: Insights from quantum quenches in one dimensional Bose gas
es"
DTSTART;VALUE=DATE-TIME:20141117T130000Z
DTEND;VALUE=DATE-TIME:20141117T140000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7318@ictp.it
DESCRIPTION:ABSTRACT\nWe consider quantum quenches in one dimensional Bose
gases where we prepare the gas in the ground state of a parabolic trap an
d then release it into a small cosine potential. This cosine potential b
reaks the integrability of the 1D gas which absent the potential is descri
bed by the Lieb-Liniger model. We explore the consequences of this cosin
e potential on the thermalization of the gas. We argue that the integrab
ility breaking of the cosine does not immediately lead to ergodicity in as
much as we demonstrate that there are residual quasi-conserved quantities
post-quench. We demonstrate that the quality of this quasi-conservation
can be made arbitrarily good.\n\n//indico.ictp.it/event/7318/
LOCATION:SISSA\, Santorio Building Cinema Room\, 1st floor
URL://indico.ictp.it/event/7318/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Entanglement and pa
rticle identity"
DTSTART;VALUE=DATE-TIME:20141118T100000Z
DTEND;VALUE=DATE-TIME:20141118T110000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7319@ictp.it
DESCRIPTION:ABSTRACT\nEntanglement of quantum states generically emerges v
ia a partial observation. Such observations are usually encoded by the o
peration of a partial trace over one of the components.of the system. Ne
vertheless it is well-known that partial trace is not suitable to deal wit
h general systems such as those involving identical particles. Recently
(Phys. Rev. Lett. 110\, 080503 (2013)) we have proposed a procedure to add
ress this problem of identical particles in a proper manner. The procedu
re is based on the properties of the algebra of observables of the system
and the GNS (Gelfand-Naimark-Siegel) construction of representations of su
ch algebra. In the present seminar\, we present our proposed approach to
this problem and discuss some of its applications and consequences. F
urther references are (arXiv:1212.1239\, arXiv:1301.1300\, arXiv:1302.4924
).\n\n//indico.ictp.it/event/7319/
LOCATION:SISSA\, Santorio Building Room 005\, 1st floor
URL://indico.ictp.it/event/7319/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Towards a holograph
ic Bose-Hubbard model"
DTSTART;VALUE=DATE-TIME:20141125T100000Z
DTEND;VALUE=DATE-TIME:20141125T110000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7323@ictp.it
DESCRIPTION:Abstract\nWe present a holographic construction of the large-N
Bose-Hubbard model. The model is based on Maxwell fields coupled to charg
ed scalar fields on the AdS2 hard wall. We realize the lobe-shaped phase s
tructure of the Bose-Hubbard model and find that the model admits Mott ins
ulator ground states in the limit of large Coulomb repulsion. In the Mott
insulator phases\, the bosons are localized on each site. We find that the
transition between Mott insulating phases with different fillings corresp
onds to first order level-crossing phase transitions. We also derive the h
olographic analog of the Mott/Superfluid phase transition between the homo
geneous and non-homogeneous phases. We then analyze the perturbations of f
ields around both the Mott insulator phase and Superfluid phase.\n\n//indi
co.ictp.it/event/7323/
LOCATION:SISSA\, Santorio Building Cinema Room\, 1st floor
URL://indico.ictp.it/event/7323/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Viscoelastic Interf
aces Driven in Disordered Media & Applications to Friction"
DTSTART;VALUE=DATE-TIME:20141128T140000Z
DTEND;VALUE=DATE-TIME:20141128T150000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7325@ictp.it
DESCRIPTION:\n Abstract:\n Many complex systems respond to a continuous in
put of energy by an accumulation of stress over time\, interrupted by sudd
en energy releases called avalanches. Recently\, it has been pointed out t
hat several basic features of avalanche dynamics are induced at the micros
copic level by relaxation processes\, which are neglected by most models.
We have studied a minimal modification of a well-known model of avalanche
dynamics\, in which we take into account the presence of "relaxation proce
sses". Precisely\, we study a viscoelastic interface driven in a disordere
d medium. \n In mean-field\, we prove that our model interface has a peri
odic behavior (with a new\, emerging time scale)\, with avalanche events t
hat span the whole system. We compute semi-analytically the friction force
acting on this surface\, and find that it is compatible with classical fr
iction experiments. \n In finite dimensions (2D)\, the mean-field system-
sized events become local\, and numerical simulations give qualitative and
quantitative results in good agreement with several important features of
real earthquakes.\n\n \n\n//indico.ictp.it/event/7325/
LOCATION:SISSA\, Santorio Building Cinema Room\, 1st floor
URL://indico.ictp.it/event/7325/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "One dimensional KPZ
growth equation and its replica solution"
DTSTART;VALUE=DATE-TIME:20141202T100000Z
DTEND;VALUE=DATE-TIME:20141202T110000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7326@ictp.it
DESCRIPTION://indico.ictp.it/event/7326/
LOCATION:SISSA\, Santorio Building Cinema Room\, 1st floor
URL://indico.ictp.it/event/7326/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Universal dynamics
of a soliton after a quantum quench"
DTSTART;VALUE=DATE-TIME:20141216T100000Z
DTEND;VALUE=DATE-TIME:20141216T110000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7331@ictp.it
DESCRIPTION:Abstract\nIn a quantum quench\, one prepares a system in an ei
genstate of a given Hamiltonian\, and then lets it evolve after suddenly c
hanging a control parameter of the Hamiltonian. By observing this evolut
ion\, one aims at understanding whether and how a quantum system reaches a
(thermal) equilibrium. Typically\, the initial state is taken to be the
ground state and/or in an extended state: we propose a different experime
ntally feasible protocol\, in which the system is prepared in an excited s
tate corresponding to a collective solitonic excitation. If we are inter
ested only in the single particle density\, in the hydrodynamic regime the
time evolution can be reduced to a semi-classical non-linear differential
equation. The study of such equation shows that the short time dynamics
after the quench is universal\, and simple analytical predictions can be
given for the velocities and profiles. Numerical support for these resul
ts is presented using the the Calogero model and the non-linear Schrodinge
r equation (NLSE)\, relevant for the implementation of the proposed protoc
ol with ultracold bosons. The effect of non-integrable terms (power-law
non-linearity and a parabolic potential) in the NLSE is also investigated\
, and shown to not spoil the universality.\n\n//indico.ictp.it/event/7331/
LOCATION:SISSA\, Santorio Building Room 005 (Ground floor)
URL://indico.ictp.it/event/7331/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Statistical aspects
of quantum state monitoring and applications"
DTSTART;VALUE=DATE-TIME:20150113T100000Z
DTEND;VALUE=DATE-TIME:20150113T110000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7347@ictp.it
DESCRIPTION:Abstract\n \nQuantum trajectories of systems subjected to con
tinuous monitoring exhibit particular stochastic behaviors such as "progre
ssive collapses" and/or ‘"quantum jumps"\, observed in various experim
ents\, but also more peculiar features\, ‘’quantum spikes’’ whic
h may be viewed as aborted jumps. This lecture will aim at describing some
statistical properties of quantum trajectories. We shall discuss statis
tical aspects of progressive non-demolition weak measurements\, as impleme
nted in cavity QED for instance. We shall present a quantitative understan
ding of the statistics of quantum spikes and of their potential universali
ty (in the sense that they are independent of the dynamical processes whic
h generate them). As an illustration\, we shall discuss a scheme to contro
l quantum flux through back-action measurement providing a potential examp
le of a mesoscopic Maxwell daemon.\n\n//indico.ictp.it/event/7347/
LOCATION:SISSA\, Santorio Building Room 005\, Ground floor
URL://indico.ictp.it/event/7347/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Spin chains with a
non compact target""
DTSTART;VALUE=DATE-TIME:20150114T090000Z
DTEND;VALUE=DATE-TIME:20150114T100000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7350@ictp.it
DESCRIPTION:Abstract\n \nMost common critical systems in condensed matter
and statistical mechanics are associated with a discrete set of critical
exponents\, which can be traced back to the compact nature of the correspo
nding field theories. There are however many noticeable cases where cont
inuous spectra of exponents are observed\, a prominent example being that
of the Integer Quantum Hall Effect. Whereas in the compact case a lot of
insight is usually gained by turning to (integrable) regularizations such
as lattice models or spin chains\, a connection between non compact field
theories and the world of integrable spin chains has for long been lackin
g. In this talk\, we will see that there actually many 'physical' spin c
hains or statistical lattice models corresponding to non compact conformal
field theories. There are many consequences to this observation\, and I
will present applications of our results to polymer physics as well as to
the construction of integrable truncations of the IQHE plateau transitons
.\nThis is based on joint work with Jesper Jacobsen (LPTENS\, Paris) and H
ubert Saleur (IPhT\, Saclay).\n\n//indico.ictp.it/event/7350/
LOCATION:SISSA\, Santorio Building Room 128\, first floor
URL://indico.ictp.it/event/7350/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Spacetime\, prime n
umbers and Riemann zeros""
DTSTART;VALUE=DATE-TIME:20150120T100000Z
DTEND;VALUE=DATE-TIME:20150120T100000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7359@ictp.it
DESCRIPTION:Polya and Hilbert conjectured long ago that the non trivial ze
ros of the Riemann zeta function are the oscillation frequencies of a phys
ical system\, a result that would lead to a proof of the celebrated Rieman
n hypothesis. In this talk we shall explain how this idea can be realize
d by the spectrum of a Dirac fermion in Rindler spacetime subject to a pot
ential constructed from the prime numbers. This result points towards unex
pected connections between Number Theory and Theoretical Physics.\n\n//ind
ico.ictp.it/event/7359/
LOCATION:SISSA\, Santorio Building Room 005\, Ground floor
URL://indico.ictp.it/event/7359/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Simulation of the f
ractional quantum Hall effect"
DTSTART;VALUE=DATE-TIME:20150127T100000Z
DTEND;VALUE=DATE-TIME:20150127T110000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7365@ictp.it
DESCRIPTION:Abstract\nWe perform an analysis of the role played by impurit
ies in the fractional quantum Hall effect\, that is\, the mechanism that c
auses\, in the lowest Landau level regime\, the formation of plateaux in t
he resistivity as a function of the magnetic applied field. To this end wi
thin the framework of quantum simulation\, we consider an impurity immerse
d in a small ultracold quantum bosonic gas trapped in a rapidly rotating p
otential (which generates an artificial magnetic field)\, an experimentall
y realistic system adequate to realize quantum Hall effects. We use exact
diagonalization for few atoms and apply the linear response theory to simu
late the transport equation. We provide a proposal of a theoretical techni
que to detect the up-to-now elusive presence of strongly correlated states
related to fractional filling factors in the context of ultracold atoms.
We analyse for the first time\, the conditions under which these strongly
correlated states are associated to the presence of the plateaux.\n\n//ind
ico.ictp.it/event/7365/
LOCATION:SISSA\, Santorio Building Room 128 (first floor)
URL://indico.ictp.it/event/7365/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Nonequilibrium fluc
tuations in quantum heat engines: Theory\, example\, and possible solid st
ate experiments"
DTSTART;VALUE=DATE-TIME:20150129T130000Z
DTEND;VALUE=DATE-TIME:20150129T140000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7366@ictp.it
DESCRIPTION:Abstract\nWe study the stochastic energetic exchanges in quant
um heat engines. Due to microreversibility\, these obey a fluctuation re
lation\, called the heat engine fluctuation relation\, which implies the C
arnot bound: no machine can have an efficiency larger than Carnot's effici
ency. The stochastic thermodynamics of a quantum heat engine (including th
e joint statistics of heat and work and the statistics of efficiency) is i
llustrated by means of an optimal two-qubit heat engine\, where each qubit
is coupled to a thermal bath and a two-qubit gate determines energy excha
nges between the two qubits. We discuss possible solid state implementatio
ns with Cooper pair boxes and flux qubits\, quantum gate operations\, and
fast calorimetric on-chip measurements of single stochastic events.\n\n//i
ndico.ictp.it/event/7366/
LOCATION:SISSA\, Santorio Building Room 005 (ground floor)
URL://indico.ictp.it/event/7366/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Form factor relocal
isation and interpolating renormalisation group flows from the staircase m
odel"
DTSTART;VALUE=DATE-TIME:20150130T130000Z
DTEND;VALUE=DATE-TIME:20150130T140000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7367@ictp.it
DESCRIPTION:Abstract\nWe investigate the staircase model\, introduced by A
liosha Zamolodchikov through an analytic continuation of the sinh-Gordon
S-matrix to describe interpolating flows between minimal models of confor
mal field theory in two dimensions. Applying the form factor expansion an
d the c-theorem\, we show that the resulting c-function has the same physi
cal content as that found by Zamolodchikov from the thermodynamic Bethe A
nsatz. This turns out to be a consequence of a nontrivial underlying mech
anism\, which leads to an interesting localisation pattern for the spectr
al integrals giving the multi-particle contributions. We demonstrate seve
ral aspects of this form factor relocalisation\, which suggests a novel a
pproach to the construction of form factors and spectral sums in integrabl
e renormalisation group flows with non-diagonal scattering.\n\n//indico.i
ctp.it/event/7367/
LOCATION:SISSA\, Santorio Building Room 005 (ground floor)
URL://indico.ictp.it/event/7367/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Temperature inversi
on in long-range interacting systems"
DTSTART;VALUE=DATE-TIME:20150217T100000Z
DTEND;VALUE=DATE-TIME:20150217T110000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7385@ictp.it
DESCRIPTION: Abstract\n \n \nTemperature inversions occur in nature\, e
.g.\, in the solar corona and in interstellar molecular clouds: somewhat c
ounterintuitively\, denser parts of the system are colder than dilute ones
. We try to understand which are the minimal ingredients and the basic phy
sical mechanism behind such phenomena. We suggest that temperature inversi
ons may spontaneously occur in a generic system with long-range interactio
ns that is prepared in an inhomogeneous thermal equilibrium state and then
brought out of equilibrium by applying an impulsive perturbation. In simi
lar situations\, short-range systems would typically relax to another ther
mal equilibrium\, with uniform temperature profile. By contrast\, in long-
range systems\, the interplay between wave-particle interaction and spatia
l inhomogeneity drives the system to nonequilibrium stationary states that
generically exhibit nonuniform temperature profiles with temperature inve
rsion. This shows how crucial the role played by the range of interparticl
e interactions is in determining the nature of steady states attained when
macroscopic systems are brought out of thermal equilibrium.\n\n//indico.i
ctp.it/event/7385/
LOCATION:ICTP Leonardo Building - Luigi Stasi Seminar Room
URL://indico.ictp.it/event/7385/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Condensed Matter and Statistical Physics seminar: "Local integrals
of motion in the many-body localized phase"
DTSTART;VALUE=DATE-TIME:20150218T150000Z
DTEND;VALUE=DATE-TIME:20150218T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7387@ictp.it
DESCRIPTION:Abstract\n \nMany-body localization is the suppression of tra
nsport in disordered\, interacting systems. It is now clear that many real
istic disordered spin and particle systems do possess such a phase and tha
t this has profound implications for the system's dynamics. Recently\, a c
haracterization of the MBL phase has been proposed in terms of the existen
ce of local integrals of motion. I will show how to build such local integ
rals of motion in perturbation theory in the interaction and how to find t
he phase boundaries. If time allows\, I will also comment on the implica
tions of this work for the performance of the quantum adiabatic algorithm.
\n Joint work with M. Müller\, V. Ros.\n\n//indico.ictp.it/event/7387
/
LOCATION:ICTP Leonardo Building - Luigi Stasi Seminar Room
URL://indico.ictp.it/event/7387/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar: "Many-body localized systems under driving"
DTSTART;VALUE=DATE-TIME:20150219T090000Z
DTEND;VALUE=DATE-TIME:20150219T100000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7388@ictp.it
DESCRIPTION:Abstract\nIsolated many-body quantum systems may fail to therm
alize due to quantum interferences. This phenomenon has the same origin as
Anderson localization and is referred to as many-body localization (MBL).
In this talk\, we will investigate how a localized system responds to an
external time-dependent driving. In particular\, we will ask whether the s
ystem absorbs energy until it reaches an infinite temperature state\, as i
t would be the case for an ergodic system\, or whether absorption eventual
ly saturates.\nCollaboration with D. Abanin\, W. De Roeck\, Z. Papic and P
. Ponte.\n\n//indico.ictp.it/event/7388/
LOCATION:ICTP Leonardo Building - Luigi Stasi Seminar Room
URL://indico.ictp.it/event/7388/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal seminar on Chemical Physics: "Modelling charge transfer i
n molecular materials: from photovoltaics to ferroelectrics"
DTSTART;VALUE=DATE-TIME:20150219T103000Z
DTEND;VALUE=DATE-TIME:20150219T113000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7389@ictp.it
DESCRIPTION:Abstract\nCharge transfer (CT) interactions between electron d
onor (D) and acceptor (A) molecules are central to many physical phenomena
in chemistry\, biology and materials science. In this talk I will present
some recent work on the modelling D/A interfaces for photovoltaic applica
tions and mixed-stack CT crystals\, for which we propose a multiscale mode
lling approach based on first-principles and model Hamiltonian electronic
structure calculations\, and classical schemes to account for electrostati
c and polarization interactions at the mesoscale.\n\n//indico.ictp.it/even
t/7389/
LOCATION:ICTP Leonardo Building - Luigi Stasi Seminar Room
URL://indico.ictp.it/event/7389/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Integrable matrix-v
alued fields and gauge theories as nonintegrable deformations"
DTSTART;VALUE=DATE-TIME:20150219T130000Z
DTEND;VALUE=DATE-TIME:20150219T140000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7394@ictp.it
DESCRIPTION:Abstract\n \nWe study in depth the (1+1)-dimensional principa
l chiral sigma model. This is an asymptotically-free N\\times N matrix-v
alued field with massive excitations. We compute all the form factors of s
everal operators combining the integrable bootstrap program and 't Hooft's
large-N limit. These results are used to compute finite volume/temperatur
e expectation values at large N. The matrix structure leads to nontrivial
thermodynamics that are not captured by the trivial large-N thermodynamic
Bethe ansatz. We also study different Yang-Mills theories in 1+1 and 2+1 d
imensions as nonintegrable deformations of the sigma model. We address the
problems of quark confinement and the glueball spectrum using ideas of fo
rm factor perturbation theory.\n\n//indico.ictp.it/event/7394/
LOCATION:SISSA\, Santorio Building Room 138 (first floor)
URL://indico.ictp.it/event/7394/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Tensor networks met
hods for lattice gauge theories"
DTSTART;VALUE=DATE-TIME:20150225T130000Z
DTEND;VALUE=DATE-TIME:20150225T140000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7397@ictp.it
DESCRIPTION:Abstract\n \nRecently tensor network methods have been exte
nded so to better address lattice gauge theories. Tensor networks can be
used either as an analytical tool to better understand lattice gauge theo
ries or as a variational ansatz for their numerical simulations. I will
present results in both directions for 2D lattice gauge theories with con
tinuous symmetry groups.\n\n//indico.ictp.it/event/7397/
LOCATION:SISSA\, Santorio Building Room 128\, first floor
URL://indico.ictp.it/event/7397/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Aspects of entangle
ment of/between disjoint regions in CFT and holography"
DTSTART;VALUE=DATE-TIME:20150303T100000Z
DTEND;VALUE=DATE-TIME:20150303T110000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7402@ictp.it
DESCRIPTION:Abstract\n \nMutual information and logarithmic negativity ar
e important quantities to understand entanglement in pure and mixed state
s. In quantum field theories they are computed by employing a method based
on the replica limit. We present a numerical method to compute the holog
raphic mutual information in AdS4 for generic shapes and another numerical
method to address the replica limit that turns out to be useful whenever
the replica limit is not known analytically\, like for the entanglement
entropy of disjoint intervals in 2D CFTs. We also discuss the logarithmic
negativity at finite temperature in 2D CFTs.\n\n//indico.ictp.it/event/74
02/
LOCATION:ICTP Leonardo Building - Luigi Stasi Seminar Room
URL://indico.ictp.it/event/7402/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Condensed Matter and Statistical Physics seminar: "Solitonic defec
ts in quenched cooled Bose-Einstein condensates"
DTSTART;VALUE=DATE-TIME:20150304T150000Z
DTEND;VALUE=DATE-TIME:20150304T160000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7401@ictp.it
DESCRIPTION:Abstract\nThe Kibble-Zurek mechanism (KZM) describes the spont
aneous formation of defects in systems that cross a second-order phase tra
nsition at a finite rate. The mechanism\, first proposed in the context
of cosmology\, is ubiquitous in nature and regards both classical and quan
tum phase transitions. We will report on the observation of the KZM on u
ltracold atoms which are rapidly cooled across the BEC phase transitions.
The defects of the order parameter\, imprinted via the KZM\, evolve into
solitonic vortices. Clear signatures of the nature of such excitations
are the twisted planar density depletion around the vortex line\, observed
after ballistic expansion\, and the double dislocation in the interferenc
e pattern obtained through homodyne techniques. Both methods allow us to
determine the sign of the quantized circulation. Experimental observati
ons agree with numerical simulations. These solitonic vortices show a ve
ry long lifetime.\n\n//indico.ictp.it/event/7401/
LOCATION:ICTP Leonardo Building - Luigi Stasi Seminar Room
URL://indico.ictp.it/event/7401/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Extensions of the G
GE hypothesis in higher dimensions"
DTSTART;VALUE=DATE-TIME:20150310T100000Z
DTEND;VALUE=DATE-TIME:20150310T110000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7404@ictp.it
DESCRIPTION:Abstract\nWe consider a d-dimensional quantum system that is p
repared in a general initial state that satisfies the cluster decompositio
n principle and evolves under a noninteracting Hamiltonian\, a setup that
can be realised by a quantum quench. We show that\, in the thermodynamic l
imit\, the dominant large time behaviour of any multipoint correlation fun
ction can be expressed in terms of the (conserved) occupations of momentum
modes of the system\, for any spatial dimension d and independently of wh
ether the system tends to a stationary state or not. This result is an ext
ension of the GGE hypothesis\, which is conjectured to describe the equili
brium properties of 1d integrable systems after a quantum quench. We furth
er show that the same reasoning suggests a precise criterion for determin
ing which conserved charges must be included in the GGE of a general 1d in
tegrable model.\n\n//indico.ictp.it/event/7404/
LOCATION:SISSA\, Santorio Building Room 128\, first floor
URL://indico.ictp.it/event/7404/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Special seminar: "Transport of Lithium ions in a LiMn_2O_4 Nanowir
e Cathode of a nano Lithium Ion Battery"
DTSTART;VALUE=DATE-TIME:20150313T100000Z
DTEND;VALUE=DATE-TIME:20150313T110000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7407@ictp.it
DESCRIPTION:Abstract\n \n \nStructural phase transition of electrode mat
erials in lithium ion batteries (LIBs) during charge-discharge processes r
esults in capacity decrease\, and it shorten the LIB life. In order to a
void capacity decrease\, we developed a nano lithium ion battery with a si
ngle LiMn2O4 nanowire as a positive electrode\, and electronic and structu
ral behavior were studied in-situ in a sub-50pm resolution electron micros
cope. The LiMn2O4 (LMO) nanowire electrode contacts with ionic liquid elec
trolyte (ILE) and LTO used as the negative electrode. The LMO nanowires ha
d\, in average\, lengths of 0.1~0.2mm and diameters of 100nm~200nm. The na
nowire electrode is free standing\, being suspended between Pt and ILE.\nT
he nanowire battery showed no capacity degradation at high charge/discharg
e rate (fully charged within 20 minutes) from the first charge/discharge c
ycle\, and structure of LMO transformed reversibly while the cyclic voltam
metry between 3.5 – 5.5 V (Li/Li+). The structure of the nanowire at the
area of ILE/LMO contact showed cubic to tetragonal phase transformation.
The other part of the nanowire showed non-equilibrium structure with a den
sity fluctuation. In the charge/discharge process 80% of the lithium ions
are transferred from the LMO nanowire and returned to it reversible\, alth
ough non-equilibrium distribution of the charge density of Lithium ions al
ong the nanowire. The dynamic of lithium ion transport at high charging ra
te (large potential difference) should be understood.\n \nReferences:\n1.
S. Lee\, et al.\, J. Phys. Chem. C 117\, 24236 (2013).\n2. S. Lee et al\,
DOI: 10.1021/nn505952k (2014).\n \n\n//indico.ictp.it/event/7407/
LOCATION:ICTP Leonardo Building - Luigi Stasi Seminar Room
URL://indico.ictp.it/event/7407/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Supersolidity in th
e bosonic Hubbard model"
DTSTART;VALUE=DATE-TIME:20150317T090000Z
DTEND;VALUE=DATE-TIME:20150317T100000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7411@ictp.it
DESCRIPTION:Abstract\n \n \nOne of the intriguing results of low tempera
ture physics in the twentieth century was the discovery of superfluidity\,
a highly coherent quantum phase of matter exhibiting frictionless flow t
hrough cavities. Even more counterintuitive was the suggestion that this
can occur in a phase of matter in which long-range crystalline order is m
aintained. In 2004 Kim and Chan [1]\, by measuring the rotational inertia
of a solid sample in torsional oscillator experiment raised the possibili
ty of a supersolid phase in helium II. The results of this experiment have
been questioned since\, the issue of supersolidity in helium II is still
open. Anderson [2] argued that the ground state of the bosonic Hubbard m
odel also exhibits a supersolid phase at integer fillings. Anderson`s arg
ument is based on the leading terms of a perturbative expression of the H
amiltonian and analyzing the response to a boundary twist [3]. In this ta
lk it is shown how a variational Monte Carlo method [4] can be constructed
based on the Baeriswyl wavefunction [5]. The scheme is equivalent to the
perturbation expansion used by Anderson\, however\, in this case the ful
l expansion is performed. The phase diagram obtained is in excellent agree
ment with quantum Monte Carlo results. We also investigate the sensitivit
y of the system to a boundary twist\, and find that it is sizeable even f
or integer fillings. To understand the nature of the phase we use a single
-particle [6] and a many-particle localization quantity [7] and find that
at integer fillings the system exhibits many-particle localization\, at
the same time\, single particles as a result of bosonic exchange\, can del
ocalize over the entire lattice. Away from integer fillings\, where the s
ystem is known to be superfluid\, delocalization is found at both the sing
le-particle and many-particle level. We interpret these results as a sign
ature of supersolidity in the Bose-Hubbard model at integer filling.\n \
nReferences:\n[1] E. Kim and M. H. W. Chan\, Science\, 305 1941 (2004).\n[
2] P. W. Anderson\, J. Low Temp. Phys.\, 169 124 (2012).\n[3] W. Kohn\, Ph
ys. Rev.\, A133 171 (1964).\n[4] B. Hetényi and B. Tanatar\, work in pro
gress.\n[5] D. Baeriswyl in Nonlinearity in Condensed Matter\, Ed. A. R. B
ishop\, D. K. Campbell\, D. Kumar\, and S. E. Trullinger\, Springer-Verlag
(1986).\n[6] A. Selloni\, P. Carnevali\, R. Car\, and M. Parrinello\, Phy
s. Rev. Lett. 59 823 (1987)\; E. S. Fois\, A. Selloni\, M. Parrinello\,
and R. Car\, J. Phys. Chem. 92 3268 (1988).\n[7] R. Resta\, Phys. Rev. Le
tt.\, 80 1800 (1998)\; R. Resta and S. Sorella\, Phys. Rev. Lett. 82 370 (
1999).\n\n//indico.ictp.it/event/7411/
LOCATION:SISSA\, Santorio Building Room 128 (first floor)
URL://indico.ictp.it/event/7411/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Spontaneous Breakin
g of U (N) symmetry in invariant Matrix Models and localization"
DTSTART;VALUE=DATE-TIME:20150324T100000Z
DTEND;VALUE=DATE-TIME:20150324T110000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7413@ictp.it
DESCRIPTION:Abstract\n \n \nMatrix Models have a strong history of succe
ss in describing a variety of situations\, from nuclei spectra to conducti
on in mesoscopic systems\, from strongly interacting systems to various as
pects of mathematical physics. Traditionally\, the requirement of base inv
ariance has lead to a factorization of the eigenvalue and eigenvector dist
ribution and\, in turn\, to the conclusion that invariant models describe
extended systems. Moreover\, Wigner-Dyson statistics for the eigenvalues i
s a hallmark of eigenvector delocalization. We show that deviations of the
eigenvalue statistics from the Wigner-Dyson universality reflects itself
on the eigenvector distribution and that a gap in the eigenvalue density b
reaks the U(N) symmetry to a smaller one. This spontaneous symmetry brea
king means that egeinvectors become localized and that the system looses e
rgodicity.\nWe also consider models with log-normal weight. Their eigenval
ue distribution is intermediate between Wigner-Dyson and Poissonian\, whic
h candidates these models for describing a system intermediate between the
extended and localized phase. We show that they have a much richer energy
landscape than expected\, with their partition functions decomposable in
a large number of equilibrium configurations\, growing exponentially with
the matrix rank. We will discuss the meaning of this energy landscape and
its implication\, commenting on the perspectives for localization problems
.\n \n- F. Franchini\; "On the Spontaneous Breaking of U(N) symmetry in i
nvariant Matrix Models"\; arXiv:1412.6523.\n- F. Franchini\; "Toward an in
variant matrix model for the Anderson Transition"\; arXiv:1503.03341.\n\n/
/indico.ictp.it/event/7413/
LOCATION:ICTP Leonardo Building - Luigi Stasi Seminar Room
URL://indico.ictp.it/event/7413/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Quantum quenches in
integrable systems: The quench action approach"
DTSTART;VALUE=DATE-TIME:20150331T120000Z
DTEND;VALUE=DATE-TIME:20150331T130000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7428@ictp.it
DESCRIPTION:Abstract\nQuantum quenches\, i.e. the coherent time evolution
of a many- body quantum system\, are one of the most studied realizations
of non- equilibrium physics. In this talk I would like to discuss a rece
nt method- the quench action approach- that allows us to obtain the post-
quench steady state for integrable systems directly in the thermodynamic l
imit. The main focus of my talk are the recent results in the N ́eel to
XXZ ( Delta >= 1) quench\, showing a failure of the GGE (based on all the
known local charges) to predict the stationary behavior of the system. If
the time suffices\, I’ll briefly discuss also some preliminary results
for the release of a hard-core bosons gas from a harmonic trap.\n\n//indi
co.ictp.it/event/7428/
LOCATION:SISSA\, Santorio Building Room 005 (ground floor)
URL://indico.ictp.it/event/7428/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Impact of hidden sy
mmetry breaking on the non-equilibrium time evolution of local observabl
es and entanglement entropies "
DTSTART;VALUE=DATE-TIME:20150410T090000Z
DTEND;VALUE=DATE-TIME:20150410T100000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7431@ictp.it
DESCRIPTION:Abstract\n \n \nI discuss some effects of (interacting) pert
urbations to the Hamiltonian of the quantum XY model in the non-equilibriu
m time evolution after a global quench. At sufficiently large times the pe
rturbations dramatically affect the expectation values of local observable
s. The leading contribution can be traced back to the breaking of non-abel
ian integrability\, which is manifest at times proportional to the inverse
perturbation strength. I describe different scenarios for the time evolut
ion of observables\, focusing on the emergence of persistent oscillations.
Finally\, I point out a scaling behaviour for the time evolution of the e
ntanglement entropies of spin blocks\, which is essentially independent of
the quench details.\n\n//indico.ictp.it/event/7431/
LOCATION:SISSA\, Santorio Building Room 005 (ground floor)
URL://indico.ictp.it/event/7431/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Condensed Matter and Statistical Physics seminar: "Combining elect
ronic-structure and enhanced-sampling molecular dynamics methods to model
fuel-cell electrodes in working conditions"
DTSTART;VALUE=DATE-TIME:20150415T140000Z
DTEND;VALUE=DATE-TIME:20150415T150000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7437@ictp.it
DESCRIPTION:Abstract\n \n \nPlatinum-group metals supported and disperse
d on highly reducible oxides are common active catalysts for the industria
l synthesis of chemical products and for renewable-energy applications suc
h as fuel cells or artificial photosynthesis. Due to the high price of Pt\
, the sustainable development of these technologies requires new materials
that reduces the content of precious metal without affecting the device e
fficiency.\n \nI will discuss the challenges opened by these systems to e
lectronic-structure modelling and will present a case study in the context
of fuel-cell electrodes. Ab-initio materials modelling is used to provide
key insight into the properties of a novel class of non-conventional cata
lysts with ultra-low metal loading.\n \nWe combine DFT simulations with a
b-initio molecular dynamics\, atomistic thermodynamics\, metadynamics\, an
d umbrella sampling methods to reveal the new surface chemistry opened by
these systems. The calculations are used to characterise the structure and
the reactivity of the electrode active sites in a wide range of compositi
ons and environments\, ranging from model surfaces at T=0K in vacuum condi
tions to realistic wet electrodes at finite temperatures\, i.e. chemical r
eactions at complex solid-liquid interfaces comprising nano-structured sur
faces in contact with a solution.\n \nThe calculated results allow for ra
tionalising the available experimental data and identify correlations amon
g the reaction mechanisms\, thermodynamic efficiency\, and local structure
of the active sites\, thus shedding light on the origins of the amplified
reactivity and stability of these novel electrodes.\n \n\n//indico.ictp.
it/event/7437/
LOCATION:ICTP Leonardo Building - Luigi Stasi Seminar Room
URL://indico.ictp.it/event/7437/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joint ICTP/SISSA Statistical Physics seminar: "Localization/Deloca
lization transition in an interacting quasi-periodic fermionic chain "
DTSTART;VALUE=DATE-TIME:20150421T090000Z
DTEND;VALUE=DATE-TIME:20150421T100000Z
DTSTAMP;VALUE=DATE-TIME:20220930T114745Z
UID:indico-event-7439@ictp.it
DESCRIPTION:\n Abstract\n \n \nWe consider a fermionic chain with an in
commensurate external potential and a short range many body interaction.\n
In absence of interaction and for potentials large enough there is Anderso
n localization as follows from KAM-type results on the spectrum of the si
ngle particle Schroedinger equation. We show the persistence of localizati
on even in presence of interaction in the intera