Finite temperature stability of a trapped dipolar Bose gas

TL;DR

This paper investigates the stability of a trapped dipolar Bose gas at finite temperatures, highlighting how trap shape, temperature, and interactions influence stability and predicting a double instability in oblate traps relevant to current experiments.

Contribution

It provides the first detailed stability diagram considering temperature, trap geometry, and short-range interactions for dipolar Bose gases.

Findings

Double instability feature in oblate traps due to thermal and anisotropic effects

Stability depends critically on trap geometry and temperature

Results inform experimental strategies for polar molecule Bose-Einstein condensates

Abstract

We calculate the stability diagram for a trapped normal Bose gas with dipole-dipole interactions. Our study characterizes the roles of trap geometry, temperature, and short-ranged interactions on the stability. We predict a robust double instability feature in oblate trapping geometries arising from the interplay of thermal gas saturation and the anisotropy of the interaction. Our results are relevant to current experiments with polar molecules and will be useful in developing strategies to obtain a polar molecule Bose-Einstein condensate.