A New Non-Abelian Topological Phase of Cold Fermi Gases in Anisotropic and Spin-Dependent Optical Lattices

TL;DR

This paper proposes that using an anisotropic and spin-dependent optical lattice enables the realization of a non-Abelian topological superfluid in cold Fermi gases with a Zeeman field smaller than the pairing gap, offering a practical approach.

Contribution

The study introduces a novel non-Abelian topological superfluid phase in cold Fermi gases using ASDOL, differing from previous isotropic lattice methods, and demonstrates its stability and edge state properties.

Findings

Non-Abelian TS phase appears with ASDOL, unlike isotropic lattices.

Zeeman field can be smaller than the pairing gap in the new phase.

The phase is stable against normal states and phase separation.

Abstract

To realize non-Abelian s-wave topological superfluid (TS) of cold Fermi gases, generally a Zeeman magnetic field larger than superfluid pairing gap is necessary. In this paper we find that using an anisotropic and spin-dependent optical lattice (ASDOL) to trap gases, a new non-Abelian TS phase appears, in contrast to an isotropic and spin-independent optical lattice. A characteristic of this new non-Abelian TS is that Zeeman magnetic field can be smaller than the superfluid pairing gap. By self-consistently solving pairing gap equation and considering the competition against normal state and phase separation, this new phase is also stable. Thus an ASDOL supplies a convenient route to realize TS. We also investigate edge states and the effects of a harmonic trap potential.