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Granulated superconductors:from the nonlinear sigma model to the Bose-Hubbard description

I. V. Yurkevich·Igor V. Lerner
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Abstract

We modify a nonlinear sigma model (NLSM) for the description of a granulated disordered system in the presence of both the Coulomb repulsion and the Cooper pairing. We show that under certain controlled approximations this model is reduced to the Bose-Hubbard (or ``dirty-boson'') model with renormalized coupling constants. We obtain a more general effective action (which is still simpler than the full NLSM action) which can be applied in the region of parameters where the reduction to the Bose-Hubbard model is not justified. This action may lead to a different picture of the superconductor-insulator transition in 2D systems.

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I. V. Yurkevich, Igor V. Lerner. 2000-09-05. Granulated superconductors:from the nonlinear sigma model to the Bose-Hubbard description. https://doi.org/10.1103/physrevb.64.054515

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