2023/07/06 by Wei-Wei Yang, Hong‐Gang Luo, Yang, Wei-Wei +2 · 3 citations
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Quantum, superfluid, helium dynamics #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.2307.03051
openalex publication_date 2023/07/06 · openalex created_date 2023/07/08 · openalex updated_date 2026/07/28
In a conventional boson system, the ground state can either be an insulator or a superfluid (SF) due to the duality between particle number and phase. This paper reveals that the long-sought Bose metal (BM) state can be realized in an exactly solvable interacting bosonic model, i.e. the Bose-Hatsugai-Kohmoto (BHK) model, which acts as the nontrivial extension of Bose-Hubbard (BH) model. By tuning the parameters such as bandwidth W, chemical potential μ, and interaction strength U, a BM state without any symmetry-breaking can be accessed for a generic W/U ratio, while a Mott insulator (MI) with integer boson density is observed at small W/U. The quantum phase transition between the MI and BM states belongs to the universality class of the Lifshitz transition, which is further confirmed by analyzing the momentum-distribution function, the Drude weight, and the superfluid density. Additionally, our investigation at finite temperature reveals similarities between the BM state and the Fermi liquid, such as a linear-T dependent heat capacity (Cv∼ γT) and a saturated charge susceptibility (χc ∼ constant) as T approaches zero. Comparing the BM state with the SF state in the standard BH model, we find that the key feature of the BM state is a compressible total wavefunction accompanied by an incompressible zero-momentum component. Given that the BM state prevails over the SF state at any finite U in the BHK model, our work suggests the possibility of realizing the BM state with on-site repulsion interactions in momentum space.