Perturbation expansion for 2-D Hubbard model
Abstract
We develop an efficient method to calculate the third-order corrections to the self-energy of the hole-doped two-dimensional Hubbard model in space-time representation. Using the Dyson equation we evaluate the renormalized spectral function in various parts of the Brillouin zone and find significant modifications with respect to the second-order theory even for rather small values of the coupling constant U. The spectral function becomes unphysical for , where W is the half-width of the conduction band. Close to the Fermi surface and for U<W, the single-particle spectral weight is reduced in a finite energy interval around the Fermi energy. The increase of U opens a gap between the occupied and unoccupied parts of the spectral function.
Cite
@article{arxiv.cond-mat/0010313,
title = {Perturbation expansion for 2-D Hubbard model},
author = {V. Zlatic and B. Horvatic and B. Dolicki and S. Grabowski and P. Entel and K. -D. Schotte},
journal= {arXiv preprint arXiv:cond-mat/0010313},
year = {2009}
}
Comments
17 pages, 11 Postscript figures, Phys. Rev. B, accepted