Discrete Hubbard-Stratonovich transformations for systems with orbital degeneracy

الأصل · EN

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.