Strong coupling theory for the superfluidity of Bose-Fermi mixtures

TL;DR

This paper presents a strong-coupling theoretical framework for superfluidity in Bose-Fermi mixtures, incorporating dynamical effects and self-consistent calculations, resulting in higher predicted transition temperatures than weak-coupling models.

Contribution

It introduces a comprehensive strong-coupling theory for fermion superfluidity in Bose-Fermi mixtures, including dynamical screening and self-energy effects, with an analytical Tc expression.

Findings

Calculated Tc is several times larger than weak coupling predictions.

Transition temperature can reach several percent of the Fermi temperature.

The theory aligns with typical 40K-87Rb mixture parameters.

Abstract

We develop a strong-coupling theory for the superfluidity of fermion pairing phase in a Bose-Fermi mixture. Dynamical screening, self-energy renormalization, and a pairing gap function are included self-consistently within the adiabatic limit (i.e., the phonon velocity is much smaller than the Fermi velocity). An analytical solution for the transition temperature (Tc) is derived within reasonable approximations. Using typical parameters of a 40K-87Rb mixture, we find that the calculated Tc is several times larger than that obtained in the weak coupling theory, and can be up to several percents of the Fermi temperature.