Dynamical emergence of a Kosterlitz-Thouless transition in a disordered Bose gas following a quench

TL;DR

This paper demonstrates that a disordered two-dimensional Bose gas can dynamically undergo a Kosterlitz-Thouless transition after a quench, with the phase outcome depending on initial conditions, supported by numerical simulations and a simple theoretical model.

Contribution

It reveals the spontaneous emergence of a Kosterlitz-Thouless transition in a non-equilibrium setting, supported by extensive simulations and a theoretical framework.

Findings

System evolves to thermal or superfluid state depending on initial conditions

Thermalization time is longer in the superfluid phase

No critical slowing down observed at the transition

Abstract

We study the dynamical evolution of a two-dimensional Bose gas after a disorder potential quench. Depending on the initial conditions, the system evolves either to a thermal or a superfluid state. Using extensive quasi-exact numerical simulations, we show that the two phases are separated by a Kosterlitz-Thouless transition. The thermalization time is shown to be longer in the superfluid phase, but no critical slowing down is observed at the transition. The long-time phase diagram is well reproduced by a simple theoretical model. The spontaneous emergence of Kosterlitz-Thouless transitions following a quench is a generic phenomenon that should arise both in the context of non-equilibrium quantum gases and nonlinear, classical wave systems.