Chiral Bosonic Topological Insulator on the Honeycomb Lattice with Anisotropic Interactions

TL;DR

This paper investigates a chiral bosonic topological insulator on a honeycomb lattice with anisotropic interactions, revealing a fractional quantum Hall state characterized by topological entanglement entropy and chiral edge states, without magnetic flux or frustration.

Contribution

It demonstrates the existence of a chiral topological insulator phase in a bosonic system on the honeycomb lattice driven by anisotropic interactions, using quantum Monte Carlo methods.

Findings

Identification of a dimer insulator phase with topological entanglement entropy ln(2)/2

Detection of chiral edge states in the phase diagram

Topological phase occurs without magnetic flux or lattice frustration

Abstract

We study hard-core bosons on the honeycomb lattice in the presence of anisotropic nearest-neighbor repulsive interactions. Using a quantum Monte Carlo (QMC) technique, we extract the phase diagram of the model in terms of the filling and the anisotropy. At half-filling we find a dimer insulator phase near maximum anisotropy that is characterized by a finite topological entanglement entropy $\ln(2)/2$, indicative of a fractional quantum Hall state for bosons. We identify the presence of edge states and derive a QMC-based method to extract and verify their chirality. Remarkably, this phase arises in the absence of magnetic flux and without explicit lattice frustration.