Study of a lattice-gas model for a prey-predator system

The study of interacting particle systems (IPS) has recently attracted grow ing interest. Also, the understanding of irreversible processes is a challe nging field in statistical physics. In this work a model of an irreversible IPS, where particles are preys and predators, is presented and studied. Th e model includes smart pursuit (predators to preys) and evasion (preys from predators). Depending on the birth and death probabilities for prey and pr edators, the model exhibits irreversible phase transitions (IPTs) between a coexistence state with coexistence of both species and an absorbing state where predator's extinction is observed. Second-order IPTs belong to the un iversality class of directed percolation as it follows from an epidemic ana lysis at criticality. (C) 1999 Published by Elsevier Science B.V. All right s reserved.