A RENORMALIZATION-GROUP APPROACH TO THE COULOMB GAP

The Coulomb Gap is a phenomenon in which the long-ranged Coulomb repul sions between localized electrons cause a soft gap to appear in the de nsity of states at the Fermi surface, dominating transport processes. A standard diagrammatic technique and a renormalization group philosop hy are applied to this problem. The density of states (which correspon ds to the two-point vertex function in our field theory) is renormaliz ed by interactions, with a correction that is logarithmic in 1D. Thus the RG is valid and an epsilon-expansion gives the density of states i n other dimensionalities. It is found that the standard Efros-Shklovsk ii theory of the Coulomb Gap is identical to the TAP theory of spin gl asses. We speculate that by means of a diagrammatic expansion for the beta-function, one can study the weak-disorder case, for which the sta ndard theory breaks down.