Coarsening dynamics of a quasi-one-dimensional driven lattice gas

We study domain growth properties of two species of particles executing biased diffusion on a half-filled square lattice, consisting of just two lanes. Driven in opposite directions by an external "electric" field, the particles form clusters due to steric hindrance. While strictly one-dimensional systems remain disordered, clusters in our "quasi-1D" case grow until only a single macroscopic cluster survives. In the coarsening regime, the average cluster size increases significantly faster than in purely diffusion-controlled systems, with an effective exponent of at least 0.6. Remarkably, however, the cluster size distribution displays dynamic scaling, following a form consistent with a diffusion-limited growth mechanism.