Emergent supercounterfluid and quantum phase diagram of two-component interacting bosons in one-dimensional optical lattice

Abstract

Motivated by a recent experiment that realizes nearest-neighbor dipolar couplings in an optical lattice [C. Lagoin, $\text{et al.}$, Nature $\text{609}$, 485 (2022)], we study a one-dimensional version of the two-component extended Bose-Hubbard model via the density-matrix renormalization group method. By using the nearest-neighbor and on-site interaction parameters from the experiment, we start by mapping the quantum phase diagram in the hopping parameters $t_{A}\mbox{-}t_{B}$ plane with boson densities $\ddot{I}{}_A=\ddot{I}{}_B=1/2$. In addition to the density wave phase reported in the experiment, we find several regimes of superfluidity when one or two hopping parameters are large enough, and interestingly there is a supercounterfluid phase at moderate and comparable hopping parameters. The universality classes of these phase transitions are analyzed from the correlation functions, excitation gaps, and entanglement entropy. In particular, a Berezinskii-Kosterlitz-Thouless type is recognized several gapped-to-gapless transitions. In addition, we also study the quantum phase transitions when varying $\ddot{I}{}_B$ from 0 to 1 while keeping $\ddot{I}{}_A=1/2$. We identify a supersolid phase in a wide range of $1/2<\ddot{I}{}_B<1$. Our work paves the way for realizing exotic many-body phases in cold atom experiments upon proper tuning of experimental parameters.

11 pages, 10 figures