Simple nonequilibrium extension of the Ising model

We introduce a simple nonequilibrium version of the Ising model, exhibiting an order-disorder phase transition. It corresponds to the competition of two different kinetic processes: one of them ordering the system and the other one disordering it (temperatures zero and infinity, respectively). Owing to the simplicity of the model, it is possible to define a pseudotemperature T characterizing the system. By using T we elucidate a striking point recently arisen in the literature, namely, how does the critical region of nonequilibrium systems compare to that of their equilibrium counterparts. Extensive numerical simulations are presented, and the conclusion is made that the model belongs in the equilibrium Ising model universality class confirming a well known conjecture. {} 1996 The American Physical Society.