Thermal fluctuations and quantum phase transition in antiferromagnetic Bose-Einstein condensates

TL;DR

This paper introduces a method to study nonequilibrium dynamics in ultracold systems, focusing on how thermal fluctuations affect quantum phase transitions in spin-1 Bose-Einstein condensates, revealing that defect scaling laws persist at low temperatures.

Contribution

It presents a novel classical fields approximation method to analyze nonequilibrium dynamics and thermal effects in ultracold quantum gases, specifically applied to antiferromagnetic Bose-Einstein condensates.

Findings

Thermal fluctuations influence the quantum phase transition.

Scaling law for spin defect creation remains valid at low temperatures.

Method effectively captures nonequilibrium dynamics in ultracold systems.

Abstract

We develop a method for investigating nonequilibrium dynamics of an ultracold system that is initially at thermal equilibrium. Our procedure is based on the classical fields approximation with appropriately prepared initial state. As an application of the method, we investigate the influence of thermal fluctuations on the quantum phase transition from an antiferromagnetic to phase separated ground state in a spin-1 Bose-Einstein condensate of ultracold atoms. We find that at temperatures significantly lower than the critical condensation temperature $T_c$ the scaling law for the number of created spin defects remains intact.