Ab initio methods for finite temperature two-dimensional Bose gases

TL;DR

This paper demonstrates that stochastic Gross-Pitaevskii equation and modified Popov theory can accurately describe finite temperature 2D Bose gases, aligning well with experimental results and removing arbitrary parameters.

Contribution

It introduces a systematic approach using modified Popov theory to eliminate the momentum cut-off parameter in classical field methods for 2D Bose gases.

Findings

Excellent agreement with experimental data

Validation of stochastic Gross-Pitaevskii equation's universality

Removal of free parameters in theoretical modeling

Abstract

The stochastic Gross-Pitaevskii equation and modified Popov theory are shown to provide an ab initio description of finite temperature, weakly-interacting two-dimensional Bose gas experiments. Using modified Popov theory, a systematic approach is developed in which the momentum cut-off inherent to classical field methods is removed as a free parameter. This is shown to yield excellent agreement with the recent experiment of Hung et al. [Nature, 470, 236 (2011)], verifying that the stochastic Gross-Pitaevskii equation captures the observed universality and scale-invariance.