A Bose gas in a single-beam optical dipole trap

TL;DR

This paper analyzes an ultracold Bose gas in a single-beam optical dipole trap, deriving analytical expressions for its properties and examining phase transition and cooling dynamics beyond harmonic approximations.

Contribution

It provides new analytical models for the density of states, critical temperature, and condensate properties in a single-beam optical dipole trap, extending beyond harmonic approximations.

Findings

Critical temperature depends on trap cutoff.

Significant deviations in evaporative cooling dynamics.

Analytical expressions for condensate properties beyond harmonic approximation.

Abstract

We study an ultracold Bose gas in an optical dipole trap consisting of one single focused laser beam. An analytical expression for the corresponding density of states beyond the usual harmonic approximation is obtained. We are thus able to discuss the existence of a critical temperature for Bose-Einstein condensation and find that the phase transition must be enabled by a cutoff near the threshold. Moreover, we study the dynamics of evaporative cooling and observe significant deviations from the findings for the well-established harmonic approximation. Furthermore, we investigate Bose-Einstein condensates in such a trap in Thomas-Fermi approximation and determine analytical expressions for chemical potential, internal energy and Thomas-Fermi radii beyond the usual harmonic approximation.