Delocalization effect of the Hubbard repulsion in exact terms and two dimensions
Abstract
The genuine physical reasons explaining the delocalization effect of the Hubbard repulsion U are analyzed. First it is shown that always when this effect is observed, U acts on the background of a macroscopic degeneracy present in a multiband type of system. After this step I demonstrate that acting in such conditions, by strongly diminishing the double occupancy, U spreads out the contributions in the ground state wave function, hence strongly increases the one-particle localization length, consequently extends the one-particle behavior producing conditions for a delocalization effect. To be valuable, the reported results are presented in exact terms, being based on the first exact ground states deduced at half filling in two dimensions for a prototype two band system, the generic periodic Anderson model at finite value of the interaction.
Cite
@article{arxiv.0804.3872,
title = {Delocalization effect of the Hubbard repulsion in exact terms and two dimensions},
author = {Zsolt Gulacsi},
journal= {arXiv preprint arXiv:0804.3872},
year = {2008}
}
Comments
23 pages, 8 figures. Accepted for publication in Phys. Rev. B