Reaching Fractional Quantum Hall States with Optical Flux Lattices

TL;DR

This paper proposes a new optical flux lattice scheme to realize bosonic fractional quantum Hall states in ultracold gases, demonstrating the emergence of topological phases with sizable energy gaps suitable for experimental observation.

Contribution

The authors introduce a novel optical flux lattice design for Jg=1 atoms that supports topological flat bands and enables the realization of fractional quantum Hall states in ultracold gases.

Findings

Bosonic fractional quantum Hall states are achievable with moderate interactions.

The lowest energy band is topological and nearly dispersionless.

Energy gaps are larger than ultracold gas temperature scales.

Abstract

We present a robust scheme by which fractional quantum Hall states of bosons can be achieved for ultracold atomic gases. We describe a new form of optical flux lattice, suitable for commonly used atomic species with groundstate angular momentum $J_g = 1$, for which the lowest energy band is topological and nearly dispersionless. Through exact diagonalization studies, we show that, even for moderate interactions, the many-body groundstates consist of bosonic fractional quantum Hall states, including the Laughlin state and the Moore-Read (Pfaffian) state. Under realistic conditions, these phases are shown to have energy gaps that are larger than temperature scales achievable in ultracold gases.