Continuum Field Description of Driven Lattice Gases

We review the critical behaviour of the Driven Lattice Gas (DLG) model. As a result, we obtain a novel Langevin equation for the DLG which depends on the microscopic transition probabilities. We then show how this dependence affects the critical behaviour of the the DLG placing the finite and the infinite driving field cases into different universality classes. Two other well known anisotropic, conservative, non-equilibrium models, the two-temperature model and the randomly driven model (RDLG) are also studied. It is shown that the RDLG with infinite averaged field and the two-temperature model with infinite parallel temperature fall in the same universality class as the infinitely driven DLG. A Langevin equation for the two-layer DLG is also presented.