Far from equilibrium dynamics of the Bose gas

TL;DR

This paper investigates the non-equilibrium dynamics of a Bose gas approaching superfluidity, highlighting the role of Josephson precession in a new universality class and providing exact and numerical results on coarsening behavior.

Contribution

It introduces the significance of a non-dissipative Josephson term in the dynamics of Bose gases and demonstrates its impact through exact solutions and numerical evidence.

Findings

Dynamic scaling applies to far from equilibrium Bose gas dynamics.

The Josephson precession term leads to a new universality class.

Numerical simulations support the proposed scaling behavior.

Abstract

We study the approach to equilibrium of a Bose gas to a superfluid state. We point out that dynamic scaling, characteristic of far from equilibrium phase-ordering systems, should hold. We stress the importance of a non-dissipative Josephson precession term in driving the system to a new universality class. A model of coarsening in d=2, involving a quench between two temperatures below the equilibrium superfluid transition temperature (T_c), is exactly solved and demonstrates the relevance of the Josephson term. Numerical results on quenches from above T_c in d=2,3 provide evidence for the scaling picture postulated.