SINGULARITIES OF A MEAN FIELD GREEN-FUNCTION

A mean field approximation allows microscopic calculations of an N-body propagator G(z) = (z-H)-1. We investigate singularities of the resulting approximate Green's function, G(mf)(z), by comparing them to the binding energies calculated by the Hartree-Fock approximation. We show that each Hartree-Fock energy induces a singularity of G(mf).