Chiral Rashba spin textures in ultra-cold Fermi gases

TL;DR

This paper proposes a practical scheme to generate Rashba spin-orbit coupling in ultra-cold Fermi gases, enabling the observation of chiral spin textures and paving the way for realizing topological superconductivity and Majorana quasiparticles.

Contribution

A new low-spontaneous-emission scheme for Rashba spin-orbit coupling in ultra-cold Fermi gases is developed, facilitating experimental observation of topological phenomena.

Findings

Scheme generates observable Fermi surface spin textures.

Chiral spin textures can lead to topological superconductivity.

Potential for realizing Majorana quasiparticles in cold atom systems.

Abstract

Spin-orbit coupling is an important ingredient in many recently discovered phenomena such as the spin-Hall effect and topological insulators. Of particular interest is topological superconductivity, with its potential application in topological quantum computation. The absence of disorder in ultra-cold atomic systems makes them ideal for quantum computation applications, however, the spin-orbit (SO) coupling schemes proposed thus far are experimentally impractical owing to large spontaneous emission rates in the alkali fermions. In this paper, we develop a scheme to generate Rashba SO coupling with a low spontaneous emission extension to a recent experiment. We show that this scheme generates a Fermi surface spin texture for $^{40}\rm{K}$ atoms, which is observable in time-of-flight measurements. The chiral spin texture, together with conventional $s$-wave interactions leads to topological superconductivity and non-Abelian Majorana quasiparticles.