Two-particle pairing and phase separation in a two-dimensional Bose gas with one or two sorts of bosons

Article

关键词: ELECTRON SPECTRAL FUNCTIONS;    ATTRACTIVE HUBBARD-MODEL;    T-J MODEL;    SUPERCONDUCTIVITY;    STATE;    SUPERFLUIDITY;    CONDENSATION;   

DOI  :  10.1103/PhysRevB.65.195103

来源: SCIE

【 摘 要 】

We present a phase diagram for a dilute two-dimensional Bose gas on a lattice. For one sort of boson we consider a realistic case of the van der Waals interaction between particles with a strong hard-core repulsion U and a van der Waals attractive tail V. For V<2t, t being a hopping amplitude, the phase diagram of the system contains regions of usual one-particle Bose-Einstein condensation (BEC). However for V>2t we have total phase separation on a Mott-Hubbard Bose solid and a dilute Bose gas. For two sorts of structureless bosons described by the two-band Hubbard model, an s-wave pairing of the two bosons of different sort not equal0 is possible. The results we obtained should be important for different Bose systems, including submonolayers of He-4, excitons in semiconductors, Schwinger bosons in magnetic systems and holons in HTSC. In the HTSC case a possibility of two-holon pairing in the slave-boson theories of superconductivity can restore a required charge 2e of a Cooper pair.

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