Optimal cooling strategies for magnetically trapped atomic Fermi-Bose mixtures

TL;DR

This paper explores optimal cooling strategies for Fermi-Bose atomic mixtures in magnetic traps, emphasizing heat capacity matching, spatial overlap, and trap frequency ratios to achieve deep Fermi degeneracy, with practical examples involving lithium and alkali metals.

Contribution

It introduces a method to optimize cooling efficiency in Fermi-Bose mixtures by adjusting trap parameters and adding a deconfining light beam, including novel insights for the 6Li-87Rb mixture.

Findings

Optimal heat capacity matching improves cooling efficiency.

Partial spatial overlap enhances Fermi degeneracy.

Deconfining light beams assist in achieving deeper degeneracy.

Abstract

We discuss cooling efficiency for different-species Fermi-Bose mixtures in magnetic traps. A better heat capacity matching between the two atomic species is achieved by a proper choice of the Bose cooler and the magnetically trappable hyperfine states of the mixture. When a partial spatial overlap between the two species is also taken into account, the deepest Fermi degeneracy is obtained for an optimal value of the trapping frequency ratio. This can be achieved by assisting the magnetic trap with a deconfining light beam, as shown in the case of fermionic 6Li mixed with 23Na, 87Rb, and 133Cs, with optimal conditions found for the not yet explored 6Li-87Rb mixture.