Gapped topological Fulde-Ferrell-Larkin-Ovchinnikov superfluids with artificial gauge potential and weak interaction

TL;DR

This paper proposes a new method to realize topological superfluids with Majorana zero modes in ultracold atoms using an artificial gauge potential, enabling topological phases with weaker interactions than previous models.

Contribution

It introduces a model using an artificial gauge potential as a substitute for Rashba spin-orbit coupling to achieve topological superfluids in ultracold atoms, especially with weak interactions.

Findings

Realization of topological superfluids with Majorana zero modes in ultracold atoms.

Identification of a large parameter regime for gapped topological FFLO superfluids.

Demonstration that weaker attractive interactions can induce topological phases.

Abstract

The topological superfluids with Majorana zero modes have not yet been realized in ultracold atoms with Rashba spin-orbit coupling. Here we show that these phases can be realized with an artificial gauge potential, which can be regarded as a site-dependent rotating Zeeman field. This potential breaks the inversion symmetry and plays the same role as Rashba spin-orbit coupling. In the inverted bands, this model can open a proper parameter regime for topological superfluids. Strikingly, we find that the interaction near the Fermi surface is dominated by the dispersion scattering in the same band, thus can realize topological phase with much weaker attractive interaction, as compared with the model with Rashba spin-orbit coupling. We find a large regime for the gapped topological Fulde-Ferrell-Larkin-Ovchinnikov superfluids and unveil the phase diagram with mean-field theory, which should be credible in the weak interaction regime. In regarding the negligible heating effect in realizing this potential in alkaline and rare-earth atoms, our model has the potential to be the first system to realize the long-sought topological FFLO phase and the associated Majorana zero modes.