First-order irreversible phase transitions in a nonequilibrium system: mean-field analysis and simulation results.

First-order irreversible phase transitions (IPT's) between an active regime and an absorbing state are studied in a single-component, two-dimensional interacting particle system by means of both simulations and a mean-field analysis. Several features obtained using the mean-field approximation such as the presence of a first-order IPT and hysteresis effects, are in excellent agreement with simulation results. In addition, extensive epidemic simulations show that the dynamical critical behavior of the system is by no means scale invariant.