Chiral Topological Orders in an Optical Raman Lattice

TL;DR

This paper proposes an optical Raman lattice setup for cold atoms that can realize chiral topological orders, including the quantum anomalous Hall effect and chiral spin liquids, with reduced heating and current experimental feasibility.

Contribution

It introduces a minimal optical Raman lattice scheme capable of producing chiral topological phases and demonstrates its advantages over conventional methods.

Findings

Realizes quantum anomalous Hall effect in single particle regime

Supports a chiral spin liquid phase in interacting regime

Reduces heating by over an order of magnitude

Abstract

We find an optical Raman lattice without spin-orbit coupling showing chiral topological orders for cold atoms. Two incident plane-wave lasers are applied to generate simultaneously a double-well square lattice and periodic Raman couplings, the latter of which drive the nearest-neighbor hopping and create a staggered flux pattern across the lattice. Such a minimal setup is can yield the quantum anomalous Hall effect in the single particle regime, while in the interacting regime it achieves the $J_1$-$J_2$-$K$ model with all parameters controllable, which supports a chiral spin liquid phase. We further show that heating in the present optical Raman lattice is reduced by more than one order of magnitude compared with the conventional laser-assisted tunneling schemes. This suggests that the predicted topological states be well reachable with the current experimental capability.