arXiv:2308.15042 · Physical Review A
Quantum phases of the biased two-chain-coupled Bose-Hubbard ladder
Jingtao Fan, Xiaofan Zhou, Suotang Jia
Abstract
We investigate the quantum phases of bosons in a two-chain-coupled ladder. This bosonic ladder is generally in a biased configuration, meaning that the two chains of the ladder can have dramatically different on-site interactions and potential energies. Adopting the numerical density-matrix renormalization-group method, we analyze the phase transitions in various parameter spaces. We find signatures of both insulating-to-superfluid and superfluid-to-insulating quantum phase transitions as the interchain tunneling is increased. Interestingly, tuning the interaction to some intermediate values, the system can exhibit a reentrant quantum phase transition between insulating and superfluid phases. We show that for infinite interaction bias the model is amenable to analytical treatment, predictions of which concerning the phase boundary are in great agreement with numerical results. We finally clarify some critical parameters which separate the system into regimes with distinct phase-transition behaviors, and we briefly compare typical properties of the biased and unbiased bosonic ladder systems. Our paper enriches Bose-Hubbard physics.