Surface tension of Bose-Einstein condensate at finite temperature

TL;DR

This paper investigates how finite temperature affects the surface tension of Bose-Einstein condensates, using theoretical models and experimental comparisons, revealing a small contribution of surface excitations in recent experiments.

Contribution

It provides a theoretical analysis of surface tension at finite temperature and an empirical relation, with comparison to experimental data for liquid helium II.

Findings

Excellent agreement between theory and experiment.

Surface excitations contribute less than 0.7% in recent BEC experiments.

An empirical relation for temperature dependence of surface tension is established.

Abstract

We examine the influence of nonzero temperature on a bounded surface of a dilute Bose gas confined by a hard wall, utilizing the Gross-Pitaevskii theory and the Bogoliubov-de Gennes equation to describe surface excitations. The theoretical calculations are compared with experimental data for liquid helium II, demonstrating excellent agreement. An empirical relation is found for the temperature-dependence of the surface tension. Furthermore, our findings indicate that the contribution of surface excitations remains below 0.7\% in the most of recent experiments on Bose-Einstein condensate.