Fractional quantum Hall states of dipolar fermions in a strained optical lattice

TL;DR

This paper demonstrates that dipolar fermions in a strained honeycomb optical lattice can host valley-polarized fractional quantum Hall states, providing a static platform to emulate quantum Hall physics.

Contribution

It introduces a method to realize fractional quantum Hall states using dipolar fermions in a strained optical lattice, a novel approach compared to traditional electronic systems.

Findings

Valley-dependent pseudomagnetic fields induce Landau levels.

Repulsive interactions stabilize fractional quantum Hall states.

Energy gaps suggest feasible experimental conditions.

Abstract

We study strongly correlated ground states of dipolar fermions in a honeycomb optical lattice with spatial variations in hopping amplitudes. Similar to a strained graphene, such nonuniform hopping amplitudes produce valley-dependent pseudomagnetic fields for fermions near the two Dirac points, resulting in the formation of Landau levels. The dipole moments polarized perpendicular to the honeycomb plane yield a long-range repulsive interaction. By exact diagonalization in the zeroth-Landau-level basis, we show that this repulsive interaction stabilizes a variety of valley-polarized fractional quantum Hall states such as Laughlin and composite-fermion states. The present system thus offers an intriguing platform for emulating fractional quantum Hall physics in a static optical lattice. We calculate the energy gaps above these incompressible states, and discuss the temperature scales required for their experimental realization.