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SUMMARY:Information and thermodynamics: optimizing information processing
using underdamped systems
DTSTART;VALUE=DATE-TIME:20231003T120000Z
DTEND;VALUE=DATE-TIME:20231003T130000Z
DTSTAMP;VALUE=DATE-TIME:20231211T031559Z
UID:indico-event-10547@ictp.it
DESCRIPTION:\n The Landauer principle states that at least kBTln2 of energ
y is required to erase a 1-bit memory\, with kBT the thermal energy of the
system. Practical erasure implementations re- quire an overhead to Landau
er’s Bound (LB)\, observed to scale as kBT × B/τ\, with τ the protoco
l duration and B close to the system relaxation time. Most model experimen
ts use overdamped systems\, for which minimizing the overhead means minimi
zing the dissipation. Underdamped systems thus sound appealing to reduce t
his energetic cost\, and are the object of this presentation. Our experime
nt implements a model 1-bit memory based on a micro-mechanical oscillator
confined in a double-well potential created by a feedback loop [1]. We mea
sure the work and the heat of informa- tion processing protocols within th
e stochastic thermodynamic framework. Our research covers all possible ope
rations on a single bit b: HOLD (b → b)\, SET (b → 0 or 1)\, NOT (b
→ ¬b).\n \n The logical SET operation is an erasure\, logically irrev
ersible\, coming with an entropic cost which is at least LB. We demonstrat
e that\, in our experiment\, this bound is reached with a 1% uncertainty\,
with protocols as short as 100 ms [2]. Besides\, we show experimentally a
nd theoretically that for underdamped systems\, fast erasures induce a hea
ting of the memory: the work influx is not instantaneously compensated by
the inefficient heat transfer to the thermostat. This temperature rise res
ults in a kinetic and potential energy contribution superseding the viscou
s dissipation term. Our model covering all damping regimes paves the way t
o new optimization strategies in information processing [3\, 4]\, includin
g the implementation of more applied logic gates performing repeated fast
operations [6].\n \n The other logical operations are reversible\, and c
an thus in principle be performed at no ther- modynamical cost. We impleme
nt the NOT operation using the momentum degree of freedom in our underdamp
ed memory to perform a bit-flip [5]. Not bounded by any entropic cost this
time\, the energetic cost of the protocol vanishes as the quality factor
of the oscillator increases\, further highlighting the low energy footprin
t and interest of underdamped memories.\n \n References\n1. S. Dago\, J
. Pereda\, S. Ciliberto and L. Bellon: JSTAT 5\, 053209 (2022)\n2. S. Dago
\, J. Pereda\, N. Barros\, S. Ciliberto\, and L. Bellon: Phys. Rev. Lett.
126\, 17 (2021)\n3. S. Dago and L. Bellon: Phys. Rev. Lett. 128\, 7 (2022)
\n4. S. Dago\, S. Ciliberto and L. Bellon: PNAS 120 (39) e2301742120\, (20
23).\n5. S. Dago and L. Bellon: Phys. Rev. E 108\, L022101\, (2023).\n6. S
. Dago\, S.Ciliberto and L.Bellon: To be published in Advanced Physics Res
earch\,\narXiv:2306.15573 (2023)\n\n//indico.ictp.it/event/10547/
LOCATION:ICTP Galileo Guest House - Fibonacci Room
URL://indico.ictp.it/event/10547/
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