Collisional cooling of ultra-cold atom ensembles using Feshbach resonances

TL;DR

This paper introduces a novel cooling method for ultra-cold fermionic atoms using energy-dependent inelastic collisions near Feshbach resonances, demonstrating potential for achieving lower temperatures than current techniques.

Contribution

It proposes a new cooling mechanism leveraging Feshbach resonances and shows how combining narrow optical or radio-frequency and broad magnetic resonances enhances cooling efficiency.

Findings

Final temperature limited by resonance width in single resonance setup

Using combined resonances improves achievable temperatures

Concrete example with $^{40}$K p-wave resonance provided

Abstract

We propose a new type of cooling mechanism for ultra-cold fermionic atom ensembles, which capitalizes on the energy dependence of inelastic collisions in the presence of a Feshbach resonance. We first discuss the case of a single magnetic resonance, and find that the final temperature and the cooling rate is limited by the width of the resonance. A concrete example, based on a p-wave resonance of $^{40}$K, is given. We then improve upon this setup by using both a very sharp optical or radio-frequency induced resonance and a very broad magnetic resonance and show that one can improve upon temperatures reached with current technologies.