THE HUBBARD-MODEL AT HIGH DIMENSIONS - SELF-CONSISTENT WEAK-COUPLING THEORY

We examine the one-band Hubbard model on a simple cubic lattice in the limit of high spatial dimensions by means of standard weak coupling theory. Various infinite series of self-energy insertions are considered as approximations for the proper self-energy. Due to the diagram collapse in the limit of infinite dimensions it is feasible to solve the resulting equations for the one-particle propagator self-consistently. The resulting one-particle spectra show a narrow peak near the Fermi energy and pronounced band tails. In particular, the relevance of the considered approximations for mass enhancement is studied.