Attractive Hofstadter-Hubbard model with imbalanced chemical and vector potentials

TL;DR

This paper investigates how imbalanced vector potentials influence the ground states of the attractive Hofstadter-Hubbard model, revealing stripe-ordered FFLO-like superfluid and supersolid phases with coexisting density waves.

Contribution

It introduces the concept of imbalanced vector potentials in the Hofstadter-Hubbard model and explores their effects on exotic superfluid and supersolid phases using mean-field theory.

Findings

Vector potentials break spatial symmetry and induce stripe-ordered phases.

Coexistence of pair-density, charge-density, and spin-density waves.

Potential realization in cold atomic gases with optical lattices.

Abstract

We study the interplay between the Hofstadter butterfly, strong interactions and Zeeman field within the mean-field Bogoliubov-de Gennes theory in real space, and explore the ground states of the attractive single-band Hofstadter-Hubbard Hamiltonian on a square lattice, including the exotic possibility of imbalanced vector potentials. We find that the cooperation between the vector potential and superfluid order breaks the spatial symmetry of the system, and flourish stripe-ordered Fulde-Ferrell-Larkin-Ovchinnikov (FFLO)-like superfluid and supersolid phases that can be distinguished and characterized according to their coexisting pair-density (PDW), charge-density (CDW) and spin-density (SDW) wave orders. We also discuss confined systems and comment on the likelihood of observing such stripe-ordered phases by loading neutral atomic Fermi gases on laser-induced optical lattices under laser-generated artificial gauge fields.