Cooling dynamics of ultracold two-species Fermi-Bose mixtures

TL;DR

This paper compares cooling strategies for ultracold Fermi-Bose mixtures, highlighting the advantages of two-color optical traps in maintaining heat capacity and enabling efficient deep Fermi degeneracy with potential superfluid signatures.

Contribution

It demonstrates that two-color optical traps can sustain a large heat capacity of bosons during cooling, improving the achievement of Fermi degeneracy and superfluid detection.

Findings

Two-color traps maintain bosonic heat capacity during cooling.

Efficient path to deep Fermi degeneracy with thermal Bose fraction.

Potential signatures of Fermi superfluid phase transition.

Abstract

We compare strategies for evaporative and sympathetic cooling of two-species Fermi-Bose mixtures in single-color and two-color optical dipole traps. We show that in the latter case a large heat capacity of the bosonic species can be maintained during the entire cooling process. This could allow to efficiently achieve a deep Fermi degeneracy regime having at the same time a significant thermal fraction for the Bose gas, crucial for a precise thermometry of the mixture. Two possible signatures of a superfluid phase transition for the Fermi species are discussed.