Excess noise for driven diffusive systems

Abstract

The steady-state scattering function for driven diffusive systems with a single conserved density is investigated in view of the intrinsically faster, as compared to the predictions of an ordinary diffusion law, spreading of density fluctuations observed in stationary driven diffusive systems at low dimensionality, and, consequently, the divergence of excess noise for small frequencies. It is found that d = 2 is the borderline dimension with marginally nondiffusive behavior; for d larger than 2 the spread is diffusive with anisotropic long-time-tail corrections. The derivations presented are confirmed by Monte Carlo simulation results for a driven hard-core lattice gas.