We calculate the one-electron spectral function of the attractive (negative- $U)$ Hubbard model. We work in the intermediate-coupling and low-density regime and obtain the self-energy in an approximate analytical form. The excitation spectrum is found to consist of three branches. The results are obtained in a framework based on the self-consistent $T$ -matrix approximation, which is compatible with the Mermin-Wagner theorem.We calculate the one-electron spectral function of the attractive (negative-$U)$ Hubbard model. We work in the intermediate-coupling and low-density regime and obtain the self-energy in an approximate analytical form. The excitation spectrum is found to consist of three branches. The results are obtained in a framework based on the self-consistent $T$-matrix approximation, which is compatible with the Mermin-Wagner theorem.

arXiv:cond-mat/9704136Physical review. B, Condensed matterMar 1, 199847 citations

Excitation spectrum of the attractive Hubbard model

R. Micnas, M. H. Pedersen, Sandra Schafroth +3 more

We study excitation-spectrum and normal-state properties of the two-dimensional attractive Hubbard model using the conserving, self-consistent T-matrix formalism in the intermediate coupling regime and at low electron concentration. Numerical results are presented for one-particle and two-particle excitation spectra, the one-particle momentum distribution, the chemical potential, and the static spin susceptibility. For a coupling strength of U/t=4.0, the one-particle spectral function, A(k,\ensuremath{\omega}), shows two peaks of different weights. One peak can be associated with pair formation, whereas the other corresponds to renormalized quasiparticle excitation. It turns out that the two-band feature is reasonably well described by an ansatz for A(k,\ensuremath{\omega}), which satisfies the first four frequency moments.We study excitation-spectrum and normal-state properties of the two-dimensional attractive Hubbard model using the conserving, self-consistent T-matrix formalism in the intermediate coupling regime and at low electron concentration. Numerical results are presented for one-particle and two-particle excitation spectra, the one-particle momentum distribution, the chemical potential, and the static spin susceptibility. For a coupling strength of U/t=4.0, the one-particle spectral function, A(k,\ensuremath{\omega}), shows two peaks of different weights. One peak can be associated with pair formation, whereas the other corresponds to renormalized quasiparticle excitation. It turns out that the two-band feature is reasonably well described by an ansatz for A(k,\ensuremath{\omega}), which satisfies the first four frequency moments.

Physical review. B, Condensed matterDec 1, 199586 citations

Spectral properties of the attractive Hubbard model

Johannes Maria Singer, T. Schneider, P. F. Meier

The European Physical Journal BJan 1, 199919 citations

Spectral function of the 1D Hubbard model

M. Gulácsi, Kevin S. Bedell

Physica B Condensed MatterApr 1, 19940 citations

We calculate the one-electron spectral function of the attractive (negative-

U)

Hubbard model. We work in the intermediate-coupling and low-density regime and obtain the self-energy in an approximate analytical form. The excitation spectrum is found to consist of three branches. The results are obtained in a framework based on the self-consistent

T

-matrix approximation, which is compatible with the Mermin-Wagner theorem.