Finite Temperature Dipolar ultra-cold Bose gas with Exchange Interactions

TL;DR

This paper develops a finite temperature theoretical framework for trapped dipolar Bose gases that includes thermal exchange interactions, providing numerical methods and analyzing their significance across different regimes.

Contribution

It introduces a numerical approach to evaluate thermal exchange interactions in dipolar Bose gases, which were previously neglected, and analyzes their impact on physical properties.

Findings

Thermal exchange interactions can be as significant as direct interactions in certain regimes.

The methodology enables accurate calculation of excitation spectra considering exchange effects.

Guidelines are provided for when thermal exchange terms can be safely neglected.

Abstract

We develop finite temperature theory for a trapped dipolar Bose gas including thermal exchange interactions. Previous treatments neglected these, difficult to compute, terms. We present a methodology for numerically evaluating the thermal exchange contributions, making use of cylindrical symmetry. We then investigate properties of the dipolar gas, including calculating the excitation spectrum over the full range of trap anisotropy. We evaluate the contributions due to thermal exchange noting that, under some regimes, these effects can be at least as significant as the direct interaction. We therefore provide guidance as to when these cumbersome terms can be neglected and when care should be exercised regarding their omission.