Berry Curvature of interacting bosons in a honeycomb lattice

TL;DR

This paper investigates how the topology of a honeycomb lattice influences the Berry curvature and induces an anomalous Hall effect in interacting bosons, using mean-field and quantum Monte Carlo methods.

Contribution

It demonstrates the emergence of non-zero Berry curvature and anomalous Hall effect in a bosonic system on a honeycomb lattice, combining theoretical and numerical approaches.

Findings

Berry curvature is non-zero for single-particle excitations.

Anomalous Hall effect observed in wavepacket dynamics.

Topological effects arise from lattice geometry and interactions.

Abstract

We consider soft-core bosons with onsite interaction loaded in the honeycomb lattice with different site energies for the two sublattices. Using both a mean-field approach and quantum Monte-Carlo simulations, we show that the topology of the honeycomb lattice results in a non-vanishing Berry curvature for the band structure of the single-particle excitations of the system. This Berry curvature induces an anomalous Hall effect. It is seen by studying the time evolution of a wavepacket, namely a superfluid ground state in a harmonic trap, subjected either to a constant force (Bloch oscillations) or to a sudden shift of the trap center.