Three-Fluid Description of the Sympathetic Cooling of a Boson-Fermion Mixture

TL;DR

This paper introduces a three-fluid model for sympathetic cooling in boson-fermion mixtures, confirming experimental limits and proposing sequential cooling to achieve temperatures below 0.1 T_F.

Contribution

The paper develops a novel three-fluid model for sympathetic cooling and suggests a sequential cooling scheme to reach lower temperatures than previously possible.

Findings

Cooling limit of about 0.2 T_F with boson-only pumping

Sequential cooling can achieve temperatures below 0.1 T_F

Model aligns with experimental observations

Abstract

We present a model for sympathetic cooling of a mixture of fermionic and bosonic atomic gases in harmonic traps, based on a three-fluid description. The model confirms the experimentally observed cooling limit of about 0.2 T_F when only bosons are pumped. We propose sequential cooling -- first pumping of bosons and afterwards fermions -- as a way to obtain lower temperatures. For this scheme, our model predicts that temperatures less than 0.1 T_F can be reached.