Phase Transitions in Lattice-Gas Models Far from Equilibrium

A lattice-gas model with particle-conserving hopping dynamics on a periodic lattice is exposed to a strong external field along one of the principal axes. The resulting stationary state is determined exactly in the limit of infinite ratio of jump rates in and perpendicular to the field direction. In this state the gas-liquid phase transition is of mean-field type. For not too strong coupling in the direction orthogonal to the field, several other phase transitions occur. All of these have mean-field character as well