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Rigorous results on superconducting ground states for attractive extended Hubbard models

Arianna Montorsi·David K. Campbell
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Abstract

We show that the exact ground state for a class of extended Hubbard models including bond-charge, exchange, and pair-hopping terms, is the Yang "eta-paired" state for any non-vanishing value of the pair-hopping amplitude, at least when the on-site Coulomb interaction is attractive enough and the remaining physical parameters satisfy a single constraint. The ground state is thus rigorously superconducting. Our result holds on a bipartite lattice in any dimension, at any band filling, and for arbitrary electron hopping.

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Arianna Montorsi, David K. Campbell. 1995-02-06. Rigorous results on superconducting ground states for attractive extended Hubbard models. https://doi.org/10.1103/physrevb.53.5153

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