DAMAGE SPREADING IN THE Q-STATE POTTS-MODEL

Dynamical evolution, in the phase space, of the ferromagnetic q-state Potts model on a square lattice is used in order to study the spread o f damage. Our results obtained by numerical Monte Carlo simulation, up dating the system by a Glauber dynamics, show that this approach is ap propriate to calculate the critical temperature T-c (the same as T-d w here the damage spreads), as well as to indicate the order of the phas e transition (second-order for q less than or equal to q(c) and first- order for q>q(c)). The present simulation on finite systems yields q(c )=7, to be compared with the exact value of q(c)=4 in the thermodynami cal limit.