Ground-state phase diagram of two-component interacting bosons on a two-leg ladder

Abstract: Using the cluster Gutzwiller mean-field method, we numerically study the ground-state phase diagram of the non-hard-core two-component interacting bosons trapped in a two-leg ladder with and without an artificial magnetic field. There are three quantum phases namely Mott insulator (MI), supercounterfluid (SCF), and superfluid (SF) are found in the phase diagram. Interestingly, several loophole SCF phases are observed at a sufficiently small intra- to inter-leg hopping ratio when the magnetic flux is absent. While if the ratio is not so small, the loophole SCF phase would disappear, but it can still be induced by applying a sufficiently large magnetic flux. Additionally, we also find that the presence of the magnetic flux leads to an enlargement of the MI lobe and the conventional SCF lobe. Moreover, the SF-MI phase boundary is quantitatively consistent with the strong-couping expansion at a weak hopping amplitude.