Temperature dependence of the energy of a vortex in a two-dimensional Bose gas

TL;DR

This paper calculates how the energy of a vortex in a 2D Bose gas depends on temperature, revealing limitations of the Thomas-Fermi approximation and providing insights into vortex creation conditions.

Contribution

It introduces a mean-field two-fluid model to evaluate the critical angular velocity for vortex formation in a 2D Bose gas at finite temperatures.

Findings

Thomas-Fermi approximation poorly predicts vortex energy profiles.

Extrapolated formula for zero-temperature critical velocity is useful up to 0.5 T_c.

Temperature influences vortex energy and critical angular velocity.

Abstract

We evaluate the thermodynamic critical angular velocity Omega_c(T) for creation of a vortex of lowest quantized angular momentum in a strictly two-dimensional Bose gas at temperature T, using a mean-field two-fluid model for the condensate and the thermal cloud. Our results show that (i) a Thomas-Fermi description of the condensate badly fails in predicting the particle density profiles and the energy of the vortex as functions of T; and (ii) an extrapolation of a simple Thomas-Fermi formula for Omega_c(0) is nevertheless approximately useful up to T = 0.5 T_c.