Phase diagram of asymmetric Fermi gas across Feshbach resonance

TL;DR

This paper maps the phase diagram of a two-component Fermi gas at zero temperature, revealing various phase separations between superfluid and normal states across different coupling strengths and polarizations near a Feshbach resonance.

Contribution

It provides a detailed analysis of phase separation regimes in asymmetric Fermi gases, including the effects of mass imbalance and coupling strength, across the BEC-BCS crossover.

Findings

Identified three types of phase coexistence between superfluid and normal phases.

Mapped how phase separation regions shift with mass imbalance and coupling strength.

Showed the phase separation regime widens or narrows depending on the majority species' mass.

Abstract

We study the phase diagram of the dilute two-component Fermi gas at zero temperature as a function of the polarization and coupling strength. We map out the detailed phase separations between superfluid and normal states near the Feshbach resonance. We show that there are three different coexistence of superfluid and normal phases corresponding to phase separated states between: (I) the partially polarized superfluid and the fully polarized normal phases, (II) the unpolarized superfluid and the fully polarized normal phases and (III) the unpolarized superfluid and the partially polarized normal phases from strong-coupling BEC side to weak-coupling BCS side. For pairing between two species, we found this phase separation regime gets wider and moves toward the BEC side for the majority species are heavier but shifts to BCS side and becomes narrow if they are lighter.