Critical behavior of random spin systems

We provide a strategy to find in few elementary calculations the critical exponents of the overlaps for dilute spin glasses, in absence of external field. Such a strategy is based on the expansion of a suitably perturbed average of the overlaps, which is used in the formulation of the free energy as the difference between a cavity part and the derivative of the free energy itself, considered as a function of the connectivity of the model. We assume the validity of certain reasonable approximations, e.g. that higher powers of overlap monomials are of smaller magnitude near the critical point, of which we do not provide a rigorous proof. King’s College London, Department of Mathematics, Strand, London WC2R 2LS, United Kingdom, and Dipartimento di Fisica, Università di Roma “La Sapienza” Piazzale Aldo Moro 2, 00185 Roma, Italy; ICTP, Strada Costiera 11, 34014 Trieste, Italy; Dipartimento di Fisica, Università di Roma “La Sapienza” Piazzale Aldo Moro 2, 00185 Roma, Italy;