Dynamical mean-field theory for the Bose-Hubbard model

Article

关键词: LIQUID HELIUM;    LATTICE MODEL;    INFINITE DIMENSIONS;    INTERACTING BOSONS;    OPTICAL LATTICES;    TRANSITION;    SUPERFLUID;    ATOMS;    SUPERCONDUCTIVITY;    INSULATOR;   

DOI  :  10.1103/PhysRevB.80.245110

来源: SCIE

【 摘 要 】

The dynamical mean-field theory (DMFT), which is successful in the study of strongly correlated fermions, was recently extended to boson systems [K. Byczuk and D. Vollhardt, Phys. Rev. B 77, 235106 (2008)]. In this paper, we employ the bosonic DMFT to study the Bose-Hubbard model which describes on-site interacting bosons in a lattice. Using exact diagonalization as the impurity solver, we get the DMFT solutions for the Green's function, the occupation density, as well as the condensate fraction on a Bethe lattice. Various phases are identified: the Mott insulator, the Bose-Einstein condensed (BEC) phase, and the normal phase. At finite temperatures, we obtain the crossover between the Mott-type regime and the normal phase, as well as the BEC-to-normal phase transition. Phase diagrams on the mu/U-t approximate to/U plane and on the T/U-t approximate to/U plane are produced (t approximate to is the scaled hopping amplitude). We compare our results with the previous ones, and discuss the implication of these results to experiments.

【 授权许可】

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