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Quench Dynamics in Interacting one-dimensional systems

Aditi Mitra (New York University)

28.06.2011 at 10:00 

Due to experiments in cold-atomic gases, the problem of

quench dynamics which is the unitary time evolution of interacting quantum systems arising due to

sudden change in system parameters has become a topic of great current interest.

Fundamental questions such as whether systems thermalize at long times after a quench,

what is the time-scale associated with thermalization, and the role played by integrability and system size

are still largely open and a frontier of current research.

In this talk I will present results for the time-evolution of some 1-dimensional models and first show how


non-thermal steady states can arise at long times, at least for exactly solvable models such as the XX

spin-chain and the Luttinger liquid.  Next I will address the issue of how stable these

steady-states are to non-trivial interactions or mode-coupling. Employing analytic approaches such as


renormalization group and random-phase-approximation, I will show that even infinitesimally weak

interactions or mode-coupling generate a dissipation (and hence a finite lifetime for the modes), and also

an effective-temperature.

However the notion of the "temperature" even with interactions is only approximate, and the

fluctuation-dissipation theorem is in general not obeyed.

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