The Gor'kov and Melik-Barkhudarov correction to an imbalanced Fermi gas in the presence of impurities

TL;DR

This paper examines how nonmagnetic impurities affect induced interactions and critical phenomena in balanced and imbalanced Fermi gases, revealing suppression of particle-hole fluctuations and implications for transition temperatures and tricritical points.

Contribution

It extends the Gor'kov and Melik-Barkhudarov correction to include impurity effects in both balanced and imbalanced Fermi gases at unitarity.

Findings

Impurities suppress particle-hole fluctuations in Fermi gases.

Induced interactions decrease transition temperature and tricritical point.

Chandrasekhar-Clogston limit is affected by impurities.

Abstract

The effects of induced interactions are calculated in both clean and dirty situations, for balanced and imbalanced Fermi gases. We investigate the effects of nonmagnetic impurities on the induced interactions corrections to the transition temperature in the case of a balanced gas, and to the tricritical point in the case of an imbalanced Fermi gas at unitarity. We find that impurities act in detriment of the induced interactions, or particle-hole fluctuations, for the transition temperature and the tricritical point. For large impurity parameter, the particle-hole fluctuations are strongly suppressed. We have also found the Chandrasekhar-Clogston limit of an imbalanced Fermi gas at unitarity considering the effects of the induced interactions, both in the pure and impurity regimes.