Dissipative two-dimensional Raman lattice

TL;DR

This paper demonstrates how a dissipative 2D Raman lattice in ultracold atoms exhibits a non-Hermitian skin effect, leading to directional density flow and unique topological edge states explained by non-Bloch theory.

Contribution

It introduces a method to engineer a dissipative 2D Raman lattice with non-Hermitian effects and analyzes its topological properties using non-Bloch band theory.

Findings

Density flow diagonal to the lattice observed

Topological edge states explained by non-Bloch theory

Directional flow detectable via condensate dynamics

Abstract

We show that a dissipative two-dimensional Raman lattice can be engineered in a two-component ultracold atomic gas, where the interplay of the two-dimensional spin-orbit coupling and lightinduced atom loss gives rise to a density flow diagonal to the underlying square lattice. The flow is driven by the non-Hermitian corner skin effect, under which eigenstates localize toward one corner of the system. We illustrate that the topological edge states of the system can only be accounted for by the non-Bloch band theory where the deformation of the bulk eigenstates are explicitly considered. The directional flow can be detected through the dynamic evolution of an initially localized condensate in the lattice, or by introducing an immobile impurity species that interact spin-selectively with a condensate in the ground state of the Raman lattice.