High-temperature expansion for steady nonequilibrium states in driven lattice gases

We develop a controlled high-temperature expansion for nonequilibrium steady states of the driven lattice gas. We represent the steady state as $P(\eta)\propto e^{-H(\eta)-\Psi(\eta)}$, and evaluate the lowest order contribution to the nonequilibrium effective interaction $\Psi(\eta)$. We see that, in dimensions $d\ge2$, all models with nonsingular transition rates have the same $\Psi(\eta)$, which consists of a three-body effective interaction decaying like $1/r^{2d+1}$. The models with the Metropolis rule show exceptional behavior.