ASYMMETRIC TWO-COMPONENT HARD-CORE BOSON MIXTURES IN A ONE-DIMENSIONAL OPTICAL LATTICE

Abstract

We study asymmetric two-component mixtures of hard-core bosons in one dimension by carrying out quantum Monte Carlo calculations. We have found that the background bosons have different roles in suppressing superfluidity depending on the degree of asymmetry and the interspecies interactions. For weak asymmetry, the superfluid stiffness is solely governed by the density of bosons with a renormalized chemical potential, whereas in the other limit with heavy background bosons, localization effects due to the interspecies interactions appear. Particularly, strong asymmetry in hopping amplitudes induces a solid phase transition at commensurate filling.