Phase diagram of a dilute fermion gas with density imbalance

TL;DR

This paper explores the phase diagram of a dilute two-component fermion gas with unequal populations and masses, revealing how mass imbalance influences stability and the emergence of exotic phases like FFLO.

Contribution

It provides the first detailed mapping of the phase diagram considering both population and mass imbalance under Feshbach resonance.

Findings

No stable uniform phase in intermediate coupling regime.

Unstable region shifts towards BEC side with heavier majority component.

Increased parameter space for FFLO state with stronger coupling.

Abstract

We map out the phase diagram of a dilute two-component atomic fermion gas with unequal populations and masses under a Feshbach resonance. As in the case of equal masses, no uniform phase is stable for an intermediate coupling regime. For majority component heavier, the unstable region moves towards the BEC side. When the coupling strength is increased from the normal phase, there is an increased parameter space where the transition is into the FFLO state. The converse is true if the majority is light.