Dipolar Bose-Einstein condensates at Finite temperature

TL;DR

This paper investigates the behavior of dipolar Bose-Einstein condensates at finite temperature using an extended Hartree-Fock-Bogoliubov theory, revealing stability and density structure effects that persist beyond zero temperature.

Contribution

It introduces a finite-temperature analysis of dipolar BECs with an approximation for dipolar exchange, extending previous zero-temperature studies.

Findings

Bi-concave condensates remain stable at finite temperature.

The central density dip in structured condensates is enhanced at low temperatures.

Condensate fraction decreases with increasing temperature.

Abstract

We study a Bose-Einstein condensate (BEC) of a dilute gas with dipolar interactions, at finite temperature, using the Hartree-Fock-Bogoliubov (HFB) theory within the Popov approximation. An additional approximation involving the dipolar exchange interaction is made to facilitate the computation. We calculate the temperature dependence of the condensate fraction of a condensate confined in a cylindrically symmetric harmonic trap. We show that the bi-concave shaped condensates found in Ref. \cite{Ronen07} in certain pancake traps at zero temperature, are also stable at finite temperature. Surprisingly, the dip in the central density of these structured condensates is actually enhanced at low finite temperatures. We explain this effect.