Path integral representation and universality class of the langevin equation for driven lattice gases

We derive the mesoscopic Langevin equation for driven lattice gas systems from microscopic driven-lattice-gas dynamics by using the generating function method developed for hard-core boson systems. We show this mesoscopic Langevin equation to be equivalent to the phenomenological Langevin equation proposed by Janssen and Schmittmann and by Leung and Cardy. Thus, we suggest that the numerical data should be analyzed with the intrinsic anisotropy taken into account in order for the numerical analysis of the critical exponents to be consistent with the theoretical analysis.