COUPLED CRITICAL MODELS - APPLICATION TO ISING-POTTS MODELS

We discuss the critical behaviour of 2D Ising and q-states Potts model s coupled by their energy density. We found new tricritical points. Th e procedure employed is the renormalisation approach of the perturbati ons series around conformal field theories representing pure models as already used for disordered spins models. This analysis could be usef ul to understand the physics of coupled critical models like the fully frustrated XY model. (C) 1997 Elsevier Science B.V.