Phase ordering kinetics of the Bose gas

TL;DR

This paper investigates the non-equilibrium dynamics of a Bose gas approaching superfluidity, highlighting the role of a Josephson precession term in defining a new universality class and supporting the scaling behavior through exact and numerical analyses.

Contribution

It introduces a model incorporating a Josephson precession term that reveals a new universality class in the phase-ordering kinetics of Bose gases.

Findings

Exact solution of a 2D coarsening model below T_c

Numerical evidence for dynamic scaling in 2D and 3D quenches

Identification of a non-dissipative Josephson term's relevance

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 dimension $d=2$, 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.