Phase transitions in the Potts spin-glass model

We have studied the Potts spin glass with two-state Ising spins and s-state Potts variables using a cluster Monte Carlo dynamics. The model recovers the +/-J Ising spin glass (SG) for s=1 and exhibits for all s a SG transition at T_SG(s) and a percolation transition at higher temperature T_p(s). We have shown that for all values of s≠1 at T_p(s) there is a thermodynamic transition in the universality class of a ferromagnetic s-state Potts model. The efficiency of the cluster dynamics is compared with that of standard spin-flip dynamics.