Discrete Hubbard-Stratonovich transformations for systems with orbital degeneracy
arXiv:cond-mat/9707035 · doi:10.1016/S0375-9601(97)00661-0
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.
4 pages, revtex, 1 eps figure, additional material avalable at http://librix.mpi-stuttgart.mpg.de/docs/ANDERSEN/fullerene/