From Nodal Ring Topological Superfluids to Spiral Majorana Modes in Cold Atomic Systems

TL;DR

This paper explores a 3D optical lattice system with spin-orbit coupling that exhibits topological superfluid phases, including nodal ring and Weyl phases, supporting Majorana modes detectable via spectroscopy.

Contribution

It introduces a new model of topological superfluid with nodal ring and Weyl phases in cold atomic systems, revealing spiral Majorana modes on the surface.

Findings

Topological superfluid with ring nodes and surface Majorana modes.

Transition to Weyl superfluid with Majorana arcs when chiral symmetry is broken.

Detection method via spatially resolved radio frequency spectroscopy.

Abstract

In this work, we consider a 3D cubic optical lattice composed of coupled 1D wires with 1D spin-orbit coupling. When the s-wave pairing is induced through Feshbach resonance, the system becomes a topological superfluid with ring nodes, which are the ring nodal degeneracies in the bulk, and supports a large number of surface Majorana zero energy modes. The large number of surface Majorana modes remain at zero energy even in the presence of disorder due to the protection from a chiral symmetry. When the chiral symmetry is broken, the system becomes a Weyl topological superfluid with Majorana arcs. With 3D spin-orbit coupling, the Weyl superfluid becomes a novel gapless phase with spiral Majorana modes on the surface. The spatial resolved radio frequency spectroscopy is suggested to detect this novel nodal ring topological superfluid phase.