Non-Hermitian skin effect in a spin-orbit-coupled Bose-Einstein condensate

TL;DR

This paper investigates the non-Hermitian skin effect in a spin-orbit-coupled Bose-Einstein condensate, revealing topological and dynamical signatures that are accessible in current cold-atom experiments.

Contribution

It introduces a non-Hermitian model for spin-orbit-coupled BECs, demonstrating the presence of the skin effect and proposing experimental detection methods.

Findings

Spectral winding confirms non-Hermitian skin effect

Eigenfunction accumulation at boundaries observed

Bulk dynamics show directional flow as a signature

Abstract

We study a Bose-Einstein condensate of ultracold atoms subject to a non-Hermitian spin-orbit coupling, where the system acquires non-Hermitian skin effect under the interplay of spin-orbit coupling and laser-induced atom loss. The presence of the non-Hermitian skin effect is confirmed through its key signatures in term of the spectral winding under the periodic boundary condition, the accumulation of eigen wavefunctions at boundaries under an open boundary condition, as well as bulk dynamics signaled by a directional flow. We show that the bulk dynamics in particular serves as a convenient signal for experimental detection. The impact of interaction and trapping potentials are also discussed based on non-Hermitian Gross-Pitaevskii equations. Our work demonstrates that the non-Hermitian skin effect and its rich implications in topology, dynamics and beyond are well within reach of current cold-atom experiments.