Gutzwiller-type projected BCS ground states for attractive Hubbard model in infinite dimensions

Yasuo Y. Suzuki*, Shin ichi Saito, Susumu Kurihara

*この研究の対応する著者

    研究成果: Article査読

    7 被引用数 (Scopus)

    抄録

    In order to develop our theoretical understanding of the superconducting state of strongly correlated electron systems, we investigate the many-body ground state of the attractive Hubbard model in infinite dimensions using the Gutzwiller-type projected BCS variational (GBCS) wave function. We first calculate various physical quantities by numerically evaluating analytical equations for systems in the thermodynamic limit. We then show that the GBCS wave function has the lowest energy when the gap parameter has a mixture of s wave and extended s wave pairing symmetry and that the ground state energy of the GBCS is lower than that of either the BCS or Fermi liquid at any electron density and any strength of the attractive interactions in our model. We also show that with infinite strength interactions, each pair of electrons with opposite spins forms a tightly bound pair on a lattice site (BEC-like state). We find a smooth crossover from a BCS-like state with large, overlapping Cooper pairs (for weakly attractive interactions) to a BEC-like state of composite bosons formed out of the tightly bound pairs of fermions (for strongly attractive interactions).

    本文言語English
    ページ(範囲)953-963
    ページ数11
    ジャーナルProgress of Theoretical Physics
    102
    5
    出版ステータスPublished - 1999 11

    ASJC Scopus subject areas

    • 物理学および天文学(全般)

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