Engineering non-Hermitian skin effect with band topology in ultracold gases

Non-Hermitian skin effect(NHSE) describes a unique non-Hermitian phenomenon that all eigen-modes are localized near the boundary, and has profound impact on a wide range of bulk properties. In particular, topological systems with NHSE have stimulated extensive research interests recently, given the fresh theoretical and experimental challenges therein. Here we propose a readily implementable scheme for achieving NHSE with band topology in ultracold gases. Specifically, the scheme realizes the one-dimensional optical Raman lattice with two types of spin-orbit coupling (SOC) and an additional laser-induced dissipation. By tuning the dissipation and the SOC strengths, NHSE and band topology can be individually controlled such that they can coexist in a considerable parameter regime. To identify the topological phase in the presence of NHSE, we have restored the bulk-boundary correspondence by invoking the non-Bloch band theory, and discussed the dynamic signals for detection. Our work serves as a guideline for engineering topological lattices with NHSE in the highly tunable environment of cold atoms, paving the way for future studies of exotic non-Hermitian physics in a genuine quantum many-body setting. The non-Hermitian skin effect comprises of boundary localised eigenmodes and has been realised in a range of 1D systems such as photonics and metamaterials. Here, the authors achieve the same effect in a quantum many-body setting using ultra-cold gases and, by tuning the strength of the spin orbit coupling, realise a non-trivial band topology.

Automated summary

The authors propose a scheme to achieve topological non-Hermitian skin effect in ultracold gases, where the strength of the spin orbit coupling is tuned to realize a non-trivial band topology.