Local-Ansatz Approach with Momentum Dependent Variational Parameters to Correlated Electron Systems

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Author(s)

    • Kakehashi Yoshiro
    • Department of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus
    • Shimabukuro Takafumi
    • Department of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus
    • Yasuda Chitoshi
    • Department of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus

Abstract

A new wavefunction which improves the Gutzwiller-type local ansatz method has been proposed to describe the correlated electron system. The ground-state energy, double occupation number, momentum distribution function, and quasiparticle weight have been calculated for the half-filled band Hubbard model in infinite dimensions. It is shown that the new wavefunction improves the local-ansatz approach (LA) proposed by Stollhoff and Fulde. Especially, calculated momentum distribution functions show a reasonable momentum dependence. The result qualitatively differs from those obtained by the LA and the Gutzwiller wavefunction. Furthermore, the present approach combined with the projection operator method CPA is shown to describe quantitatively the excitation spectra in the insulator regime as well as the critical Coulomb interactions for a gap formation in infinite dimensions.

Journal

  • Journal of the Physical Society of Japan

    Journal of the Physical Society of Japan 77(11), 114702-114702, 2008

    THE PHYSICAL SOCIETY OF JAPAN

Codes

  • NII Article ID (NAID)
    130005436207
  • Text Lang
    ENG
  • ISSN
    0031-9015
  • Data Source
    J-STAGE 
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