Two-Dimensional Hubbard Model at Low Electron Density

Hidetoshi Fukuyama, Yasumasa Hasegawa, Osamu Narikiyo

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50 Citations (Scopus)


The two dimensional Hubbard model with repulsive interaction is studied in the t-matrix approximation, which is the valid approximation in low electron density. The particle-particle correlation function and the t-matrix are obtained analytically. By use of these analytical results it is shown that the t-matrix and hence the self-energy have no singularities in the upper half plane of the complex energy variable. The phase angle δ(2kF + q, ω), with kF being the Fermi wave vector, in the limit of q=0 and ω = 0 is found to depend strongly on the ratio ω/q and is not always zero. The case of the attractive interaction is also briefly studied.

Original languageEnglish
Pages (from-to)2013-2030
Number of pages18
Journaljournal of the physical society of japan
Issue number6
Publication statusPublished - Jan 1991
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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