Pairing in Asymmetrical Fermi Systems with Intra- and Inter-Species Correlations

Abstract

We consider inter- and intra-species pairing interactions in an asymmetrical Fermi system. Using equation of motion method, we obtain coupled mean-field equations for superfluid gap functions and population densities. We construct a phase diagram across BCS-BEC regimes. Due to intra-species correlations, the BCS singlet superfluid state can sustain finite polarizations, $P$. For larger $P$, we find phase separations in BCS and BEC regimes. A superfluid phase exists for all $P$ deep in BEC regime. Our results may apply to pairing in ultracold fermions, nuclear and quark matter physics.