Thermalization in mixtures of ultracold gases

TL;DR

This paper studies how different factors influence the thermalization process in two-species ultracold gases, revealing dependencies on scattering interference and trap parameters through coupled Boltzmann equations.

Contribution

It introduces a detailed analysis of thermalization times considering partial wave interferences and trap effects, extending understanding beyond collision rates.

Findings

Thermalization times depend on scattering partial wave interferences.

In harmonic traps, thermalization dynamics are influenced by the ratio of collision rate to trap frequencies.

Thermalization times differ significantly from collision rates, highlighting complex underlying physics.

Abstract

Starting from a set of coupled Boltzmann equations, we investigate the thermalization of a two-species cold atomic gas confined either in a box or in an isotropic harmonic trap. We show that the thermalization times, by contrast to the collision rate, depend on the interferences between scattering partial waves. The dynamics of thermalization in a harmonic trap is also strongly dependent upon the ratio between the collision rate and the trap frequencies.