Topological phases of lattice bosons with a dynamical gauge field

TL;DR

This paper investigates topological phases in lattice bosons influenced by dynamical gauge fields, revealing a phase transition between two topologically non-trivial states as interactions vary, using exact diagonalization and Chern number calculations.

Contribution

It introduces a detailed analysis of how dynamical gauge fields affect topological phases in lattice bosons, highlighting a phase transition driven by interaction strength.

Findings

Dynamical gauge fields enhance topological effects in lattice bosons.

A phase transition occurs between two topologically non-trivial phases.

Exact diagonalization confirms the topological nature via Chern number calculations.

Abstract

Optical lattices with a complex-valued tunnelling term have become a standard way of studying gauge-field physics with cold atoms. If the complex phase of the tunnelling is made density-dependent, such system features even a self-interacting or dynamical magnetic field. In this paper we study the scenario of a few bosons in either a static or a dynamical gauge field by means of exact diagonalization. The topological structures are identified computing their Chern number. Upon decreasing the atom-atom contact interaction, the effect of the dynamical gauge field is enhanced, giving rise to a phase transition between two topologically non-trivial phases.