Power law decay of correlations in stationary nonequilibrium lattice gases with conservative dynamics

We report computer simulations and high-temperature approximations of the pair correlation in a stationary nonequilibrium system, a lattice gas subject to a strong uniform driving field E. The dynamics of the system is given by hoppings of particles to adjacent empty sites with rates biased for jumps in the direction of E. We study the anisotropic short-distance behavior as well as the long-distance decay properties of the two-point correlations along the principal axes. The simulations as well as the (approximate) expansion in ..beta.. strongly suggest that the correlations in this system have a power law decay, r/sup -D/ for dimensions D = 2 and 3, even at high temperatures.