Spectral weight of the hubbard model through cluster perturbation theory
We calculate the spectral weight of the one- and two-dimensional Hubbard models by performing exact diagonalizations of finite clusters and treating intercluster hopping with perturbation theory. Even with relatively modest clusters (e.g., 12 sites), the spectra thus obtained give an accurate description of the exact results. Spin-charge separation (i.e., an extended spectral weight bounded by singularities dispersing with wave vector) is clearly recognized in the one-dimensional Hubbard model, and so is extended spectral weight in the two-dimensional Hubbard model.
Senechal
D
Centre de Recherche sur les Proprietes Electroniques de Materiaux Avances et Departement de Physique, Universite de Sherbrooke, Sherbrooke, Quebec, Canada J1K 2R1.
Perez
D
Pioro-Ladriere
M