  A reformulation of site-occupation embedding theory (SOET) in terms of
Green's functions is presented. Referred to as site-occupation--Green's
function embedding theory (SOGET), this novel extension of density-functional
theory for model Hamiltonians shares many features with dynamical mean-field
theory (DMFT) but is formally exact (in any dimension). In SOGET, the
impurity-interacting correlation potential becomes a density-functional
self-energy which is frequency-dependent and in principle non-local. A simple
local density-functional approximation (LDA) combining the Bethe Ansatz (BA)
LDA with the self-energy of the two-level Anderson model is constructed and
successfully applied to the one-dimensional Hubbard model. Unlike in previous
implementations of SOET, no many-body wavefunction is needed, thus reducing
drastically the computational cost of the method.
