Spin - orbital-angular-momentum coupling in Bose-Einstein condensates

TL;DR

This paper proposes implementing spin-orbital-angular-momentum coupling in Bose-Einstein condensates using Laguerre-Gaussian beams, studying their phase diagrams and potential for gravitational detection, opening new avenues in superfluid physics.

Contribution

It introduces a novel method to realize spin-orbital-angular-momentum coupling in ultracold atoms and analyzes its ground-state phases and applications.

Findings

Ground-state phase diagrams of SOAM-coupled BECs on a ring trap are mapped.

Potential application of SOAM coupling in gravitational force detection.

Foundation laid for exploring superfluid physics with SOAM coupling.

Abstract

Spin-orbit coupling (SOC) plays a crucial role in many branches of physics. In this context, the recent experimental realization of the coupling between spin and linear momentum of ultracold atoms opens a completely new avenue for exploring new spin-related superfluid physics. Here we propose that another important and fundamental SOC, the coupling between spin and orbital angular momentum (SOAM), can be implemented for ultracold atoms using higher-order Laguerre-Gaussian laser beams to induce Raman coupling between two hyperfine spin states of atoms. We study the ground-state phase diagrams of SOAM-coupled Bose-Einstein condensates on a ring trap and explore their applications in gravitational force detection. Our results may provide the basis for further investigation of intriguing superfluid physics induced by SOAM coupling, such as collective excitations.