Anisotropic Superfluidity in the Two-Species Polar Fermi Gas

TL;DR

This paper investigates anisotropic superfluidity in a two-species polar Fermi gas, revealing complex pairing behaviors influenced by isotropic and anisotropic interactions, with implications for phase transitions and superfluid properties.

Contribution

It introduces the effects of combined isotropic and anisotropic interactions on superfluid pairing and identifies potential pairing symmetry transitions in heteronuclear fermionic molecules.

Findings

Ellipsoidal momentum distribution characterized by a deformation parameter.

Identification of momentum-dependent features of the superfluid order parameter.

Critical temperatures suggest possible pairing symmetry transition.

Abstract

We study the superfluid pairing in a two-species gas of heteronuclear fermionic molecules with equal density. The interplay of the isotropic s-wave interaction and anisotropic long-range dipolar interaction reveals rich physics. We find that the single-particle momentum distribution has a characteristic ellipsoidal shape that can be reasonably represented by a deformation parameter $\alpha$ defined similarly to the normal phase. Interesting momentum-dependent features of the order parameter are identified. We calculate the critical temperatures of both the singlet and triplet superfluid, suggesting a possible pairing symmetry transition by tuning the s-wave or dipolar interaction strength.