A quantum Monte Carlo study of the two-component mixture of hard-core bosons in one dimension

T. Onogi, Yoshimasa Murayama

Min-Chul Cha

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.

Viktor Cikojević

Massimo Boninsegni, Nikolay V. Prokof'ev

We have studied by quantum Monte Carlo simulations the low temperature phase diagram of a mixture of isotopic, hard core bosons, described by the $t\text{\ensuremath{-}}{J}_{z}\text{\ensuremath{-}}{J}_{\ensuremath{\perp}}$ model, with ${J}_{\ensuremath{\perp}}=\ensuremath{\alpha}{J}_{z}$. The coexistence of superfluid hole-rich and insulating, antiferromagnetically ordered hole-free phases is observed at sufficiently low hole density for any $\ensuremath{\alpha}<1$. A two-component checkerboard supersolid phase is not observed. The experimental relevance and possible broader implications of these findings are discussed.

Ji-Woo Lee, Min-Chul Cha

Akiko Masaki-Kato, Seiji Yunoki, Dai S. Hirashima

We study the superfluid density of hard-core bosons on quasi-one-dimensional lattices using the quantum Monte Carlo method. Because of phase slippage, the superfluid density drops quickly to zero at finite temperatures with increasing the system length $\ensuremath{\ell}$ and the superfluid transition temperature is zero in one spatial dimension and also in quasi-one dimension in the limit of $\ensuremath{\ell}\ensuremath{\rightarrow}\ensuremath{\infty}$. We calculate the superfluid density of a model where no phase slippage is allowed and show that the superfluid density remains finite at finite temperatures even in the one-dimensional limit. We also discuss how finite superfluid density can be observed in a quasi-one-dimensional system using a torsional oscillator.