Probing Majorana fermions in spin-orbit coupled atomic Fermi gases

TL;DR

This paper theoretically demonstrates how to visualize Majorana fermions in a spin-orbit coupled ultracold atomic Fermi gas, showing their signatures in density measurements during a topological phase transition.

Contribution

It provides a detailed analysis of Majorana fermion detection in ultracold gases and offers realistic experimental parameters for observing these particles.

Findings

Majorana fermions are visible at vortex cores via density measurements.

The topological phase transition can be controlled by the Zeeman field.

Experimental conditions for observing Majorana fermions are estimated.

Abstract

We examine theoretically the visualization of Majorana fermions in a two-dimensional trapped ultracold atomic Fermi gas with spin-orbit coupling. By increasing an external Zeeman field, the trapped gas transits from non-topological to topological superfluid, via a mixed phase in which both types of superfluids coexist. We show that the zero-energy Majorana fermion, supported by the topological superfluid and localized at the vortex core, is clearly visible through (i) the core density and (ii) the local density of states, which are readily measurable in experiment. We present a realistic estimate on experimental parameters for ultracold $^{40}$K atoms.