Phase transitions of the coherently coupled two-component Bose gas in a square optical lattice

Bornheimer, Ulrike; Vasić, Ivana; Hofstetter, Walter

Phase transitions of the coherently coupled two-component Bose gas in a square optical lattice

Files

PhysRevA.96.063623.pdf(1.82 MB)

Date

2017-12-28

Authors

Bornheimer, Ulrike

Vasić, Ivana

Hofstetter, Walter

Journal Title

Physical Review A

Volume Title

96

Article Title

063623

Publisher

American Physical Society

Abstract

We investigate properties of an ultracold, two-component bosonic gas in a square optical lattice at unit filling. In addition to density-density interactions, the atoms are subject to coherent light-matter interactions that couple different internal states. We examine the influence of this coherent coupling on the system and its quantum phases by using Gutzwiller mean-field theory as well as bosonic dynamical mean-field theory. We find that the interplay of strong interspecies repulsion and coherent coupling affects the Mott insulator to superfluid transition and shifts the tip of the Mott lobe toward higher values of the tunneling amplitude. In the strongly interacting Mott regime, the resulting Bose-Hubbard model can be mapped onto an effective spin Hamiltonian that offers additional insights into the observed phenomena.