Pairing Symmetry in the Anisotropic Fermi Superfluid under p-wave Feshbach Resonance

TL;DR

This paper theoretically investigates the pairing symmetry in an anisotropic Fermi superfluid under p-wave Feshbach resonance, revealing how it depends on dipole interactions and can be experimentally identified.

Contribution

It identifies the ground state pairing symmetry as dependent on dipole interaction strength and proposes experimental methods to determine it.

Findings

Pairing symmetry is $k_z$ for strong dipole interaction.

Pairing symmetry becomes $k_z - i eta k_y$ for weak dipole interaction.

A phase transition between these states can be driven by external magnetic field or density.

Abstract

The anisotropic Fermi superfluid of ultra-cold Fermi atoms under the p-wave Feshbach resonance is studied theoretically. The pairing symmetry of the ground state is determined by the strength of the atom-atom magnetic dipole interaction. It is $k_z$ for a strong dipole interaction; while it becomes $k_z - i \beta k_y$, up to a rotation about z, for a weak one (Here $\beta$ < 1 is a numerical coefficient). By changing the external magnetic field or the atomic gas density, a phase transition between these two states can be driven. We discuss how the pairing symmetry of the ground state can be determined in the time-of-flight experiments.