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arXiv · 0804.3872

Delocalization effect of the Hubbard repulsion in exact terms and two dimensions

Zsolt Gulacsi
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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.

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Zsolt Gulacsi. 2008-04-24. Delocalization effect of the Hubbard repulsion in exact terms and two dimensions. https://doi.org/10.1103/physrevb.77.245113

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