PHASE TRANSITION IN A NONEQUILIBRIUM POTTS MODEL WITH COMPETING DYNAMICS: A MONTE-CARLO STUDY

The nonequilibrium steady state of three-state Potts model evolving under combined Glauber dynamics at temperature \beta^-1 and Kawasaki dynamics at \beta′= 0 is studied by Monte-Carlo simulations. As the exchange rate p increases, the phase transition changes from second to first order. The critical exponents of second-order transition are independent of p, and the critical properties for different p belong to the same universality class.