Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physica C Superconductivity

Two-dimensional Hubbard model in low electron density limit

Osamu Narikiyo, Yasumasa Hasegawa, Hidetoshi Fukuyama

Published Dec 1, 1991• 1 citation
Publisher
DOI
10.1016/0921-4534(91)90895-6

Related papers

Two-dimensional Hubbard model at low-electron density

修 成清

•Jan 1, 1992•1 citation

Superconductivity in the two-dimensional t-J model at low electron density

M. Yu. Kagan, Thomas Maurice Rice

The two-dimensional t-J model at low electron densities is unstable against various forms of electron pairing at low enough temperatures. At parameter values J/t<<1, the leading instability, although only at very low temperature, is to p-wave pairing similar to the Hubbard model. At values of J/t>1, an instability against d-wave pairing sets in at a higher temperature as found numerically by Dagotto et al (1993). In addition, at values of J/t>2, which are beyond the threshold for a bound state in the low-electron-density limit, a region of predominantly s-wave pairing is found.

Journal of Physics Condensed Matter•May 16, 1994•62 citations

Two-Dimensional Hubbard Modelat Low Electron Density

Hidetoshi Fukuyama, Yasumasa Hasegawa, Osamu Narikiyo

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(2 k F + q , ω), with k F 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.

Journal of the Physical Society of Japan•Jun 15, 1991•70 citations

THE TWO-DIMENSIONAL HUBBARD MODEL WITH STRONG ELECTRON REPULSION

L. B. Ioffe, A. I. Larkin

International Journal of Modern Physics B•Aug 1, 1987•1 citation

Recent numerical results on the two dimensional Hubbard model

Alberto Parola, Sandro Sorella, Stefano Baroni A +3 more

Physica C Superconductivity•Dec 1, 1989•22 citations

Perturbation Theory and Singularities in Two-Dimensional Hubbard Model at Low Electron Density

Hidetoshi Fukuyama, Osamu Narikiyo, Yasumasa Hasegawa

The two-dimensional Hubbard model has been studied in the region of low electron density based on the t -matrix approximation. This can take proper account of the singular behaviors of the forward scattering whose importance was indicated by Anderson. By performing first the angular integrations in the irreducible particle-particle correlation function, we can prove analytically that all of the poles of the t -matrix lie on the real axis. Hence the t -matrix and then the self-energy of the retarded Green function, Σ( k , z ), are analytic in the upper half-plane of the energy variable, z . This, together with Im Σ( k F , ε+i δ)∝ε 2 ln |ε|, leads to the conclusion that the electrons described by the two-dimensional Hubbard model are Fermi liquid, at least in the region of low electron density.

Journal of the Physical Society of Japan•Feb 15, 1991•33 citations
The two-dimensional t-J model at low electron densities is unstable against various forms of electron pairing at low enough temperatures. At parameter values J/t<<1, the leading instability, although only at very low temperature, is to p-wave pairing similar to the Hubbard model. At values of J/t>1, an instability against d-wave pairing sets in at a higher temperature as found numerically by Dagotto et al (1993). In addition, at values of J/t>2, which are beyond the threshold for a bound state in the low-electron-density limit, a region of predominantly s-wave pairing is found.
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(2 k F + q , ω), with k F 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.
The two-dimensional Hubbard model has been studied in the region of low electron density based on the t -matrix approximation. This can take proper account of the singular behaviors of the forward scattering whose importance was indicated by Anderson. By performing first the angular integrations in the irreducible particle-particle correlation function, we can prove analytically that all of the poles of the t -matrix lie on the real axis. Hence the t -matrix and then the self-energy of the retarded Green function, Σ( k , z ), are analytic in the upper half-plane of the energy variable, z . This, together with Im Σ( k F , ε+i δ)∝ε 2 ln |ε|, leads to the conclusion that the electrons described by the two-dimensional Hubbard model are Fermi liquid, at least in the region of low electron density.