Generalized Rashba spin-orbit coupling for cold atoms

TL;DR

This paper proposes a new type of spin-orbit coupling for cold atoms using laser-induced interactions, specifically a Rashba-type coupling for a spin 1 system, with potential applications demonstrated through negative refraction phenomena.

Contribution

It introduces a generalized Rashba spin-orbit coupling scheme for cold atoms, extending previous models to a spin 1 system and exploring its experimental implementation.

Findings

Enhanced negative refraction amplitude compared to spin 1/2 Rashba coupling

Feasible implementation using stimulated Raman couplings in alkali atoms

Theoretical analysis of the coupling scheme and its effects

Abstract

We study the possibility to generate a new type of spin-orbit coupling for the center of mass motion of cold atoms, using laser beams that resonantly couple N atomic internal ground states to an extra state. After a general analysis of the scheme, we concentrate on the tetrapod setup (N=4) where the atomic state can be described by a three-component spinor, evolving under the action of a Rashba-type spin-orbit coupling for a spin 1 particle. We illustrate a consequence of this coupling by studying the negative refraction of atoms at a potential step, and show that the amplitude of the refracted beam is significantly increased in comparison to the known case of spin 1/2 Rashba coupling. Finally we explore a possible implementation of this tetrapod setup, using stimulated Raman couplings between Zeeman sublevels of the ground state of alkali atoms.