Two-leg ladder Bose Hubbard models with staggered fluxes

TL;DR

This paper studies the ground state phases of ultracold atoms in a two-leg ladder with staggered magnetic flux, revealing superfluid and Mott-insulator phases, and characterizing current patterns.

Contribution

It introduces a combined analytical and numerical approach to analyze superfluid phases and current configurations in a staggered flux Bose-Hubbard ladder.

Findings

Identification of stable superfluid phases and phase boundaries.

Observation of staggered vortex and anti-vortex current patterns.

Confirmation of analytical results with numerical simulations.

Abstract

We investigate the ground state properties of ultracold atoms trapped in a two-leg ladder potential in the presence of an artificial magnetic field in a staggered configuration. We focus on the strongly interacting regime and use the Landau theory of phase transitions and a mean field Gutzwiller variational method to identify the stable superfluid phases and their boundaries with the Mott-insulator regime as a function of magnetic flux. In addition, we calculate the local and chiral currents of these superfluid phases, which show a staggered vortex anti-vortex configuration. The analytical results are confirmed by numerical simulations using a cluster mean-field theory approach.