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Assisted hopping in the Anderson impurity model: A flow equation study

T. Stauber·F. Guinea
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Abstract

We investigate the effect of assisted hopping in the Anderson impurity model. We use the flow equation method, which, by means of unitary transformations, generates a sequence of Hamiltonians in order to eliminate the assisted hopping terms. This approach yields a renormalized on-site energy $ε_d^*$, a renormalized correlation energy $U^*$ and other terms, which include pair hopping. For some parameter values, the initial Hamiltonian flows towards an attractive Anderson model. We argue that this result implies a tendency towards local pairing fluctuations.

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T. Stauber, F. Guinea. 2004-02-03. Assisted hopping in the Anderson impurity model: A flow equation study. https://doi.org/10.1103/physrevb.69.035301

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