Joint ICTP/SISSA Statistical Physics seminar: "Localization and glassy dynamics of many-body quantum systems"
Starts 25 Oct 2011 12:00
Ends 25 Oct 2011 20:00
Central European Time
Leonardo da Vinci Building Luigi Stasi Seminar Room
Strada Costiera, 11
I - 34151 Trieste (Italy)
When classical systems fail to explore their entire configurationalspace, intriguing macroscopicphenomena like aging and glass formation may emerge. Also closed quanto-mechanical systems may stop wandering freely around the whole Hilbert space, even if they are initially prepared into a macroscopically large combination of eigenstates. This phenomenon is actually known to occur in presence of disorder and manifests itself either by
single-particle  or many-particle  wavefunction localization. However, alike classical models for glassy behavior, ergodicity breakdown may not necessarily require disorder.  In this talk I will report numerical evidences that the dynamics of strongly interacting lattice bosons driven sufficiently far from equilibrium can be trapped into extremely long-lived inhomogeneous metastable states.  The slowing down of incoherent density excitations above a threshold energy, much reminiscent of a dynamical arrest on the verge of a glass transition, is identified as the key feature of this phenomenon. We argue that the resulting long-lived inhomogeneities are responsible for the lack of thermalization observed in large systems.  Such a rich phenomenology could be experimentally uncovered upon probing the out-of-equilibrium dynamics of conveniently prepared quantum states of trapped cold atoms which I will discuss. The approach used to extensively investigate this phenomenon is based both on the exact solution of the quantum dynamics and on a novel real- time variational Quantum Monte Carlo method we have introduced.  The latter approach offers a reliable accuracy and stability in the study of 1-dimensional systems while also o_ering a seamless exploration of higher dimensional geometries.
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