Renormalization group approach to spin glass systems

A renormalization group transformation suitable for spin glass models and, more generally, for disordered models, is presented. The procedure is non-s tandard in both the nature of the additional interactions and the coarse gr aining transformation, that is performed on the overlap probability measure . Universality classes are thus naturally defined on a large set of models, going from Z(2) and Gaussian spin glasses to Ising and fully frustrated mo dels, and others. The proposed analysis is tested numerically on the Z(2) E dwards-Anderson model in d = 4. Good estimates of the critical index v and of T-c are obtained, and an RG flow diagram is sketched for the first time.