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Gutzwiller variational theory for the Hubbard model with attractive interaction

Joerg Buenemann·Florian Gebhard·Katalin Radnoczi·Patrik Fazekas
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Abstract

We investigate the electronic and superconducting properties of a negative-U Hubbard model. For this purpose we evaluate a recently introduced variational theory based on Gutzwiller-correlated BCS wave functions. We find significant differences between our approach and standard BCS theory, especially for the superconducting gap. For small values of $|U|$, we derive analytical expressions for the order parameter and the superconducting gap which we compare to exact results from perturbation theory.

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Joerg Buenemann, Florian Gebhard, Katalin Radnoczi, Patrik Fazekas. 2005-03-14. Gutzwiller variational theory for the Hubbard model with attractive interaction. https://doi.org/10.1088/0953-8984%2F17%2F25%2F007

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