Physics (Internal)

Statistical Mechanics of Periodically-driven Open Quantum Systems

This event is part of the Preliminary Oral Exam.

Examining Committee: Claudio Chamon, Michael El-Batanouny, So-Young Pi, Anatoli Polkovnikov

Abstract: Quantum systems driven periodically in time have received a great amount of theoretical and experimental attention in recent years, especially in the context of cold atomic gases. However, as a host of recent experiments illustrate, driving solid-state materials out of equilibrium holds the promise to dramatically alter their equilibrium phase diagrams, and even to induce new phases inaccessible at equilibrium. Understanding the “periodic thermodynamics” of such driven systems, which are inevitably open to the environment, is necessary in order to explore this exciting landscape theoretically. In this talk, I will provide an overview of the current state of this problem, and outline various results that speak to the “big picture” of periodic thermodynamics. The focus of the discussion will be on the possibility, or impossibility, of periodically-driven systems reaching quasi-thermal steady states at long times when dissipation is included. First, I will explore a class of exactly solvable models that allow one to study this question in detail. I will discuss examples where systems in this class reach effective thermal steady states, and other examples where they do not, and will comment on conditions for the emergence of such steady states. I will also discuss more recent results on the role of the bath in limiting the formation of effective thermal steady states in more generic systems.