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Discrete Hubbard-Stratonovich transformations for systems with orbital degeneracy

O. Gunnarsson·E. Koch
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Abstract

A discrete Hubbard-Stratonovich transformation is presented for systems with an orbital degeneracy $N$ and a Hubbard Coulomb interaction without multiplet effects. An exact transformation is obtained by introducing an external field which takes $N+1$ values. Alternative approximate transformations are presented, where the field takes fewer values, for instance two values corresponding to an Ising spin.

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O. Gunnarsson, E. Koch. 1997-07-03. Discrete Hubbard-Stratonovich transformations for systems with orbital degeneracy. https://doi.org/10.1016/s0375-9601(97)00661-0

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