Long-range order in a quasi one-dimensional non-equilibrium three-state lattice gas

Biased diffusion of two species with conserved dynamics on a 2 x L periodic lattice is studied via Monte Carlo simulations. In contrast to its simple one-dimensional version on a ring, this quasi one-dimensional model surpris ingly exhibits phase separation in its steady state, which is characterized by one macroscopic particle cluster. We study the order parameter and the cluster-size distributions as a function of the system size L, to support t he above picture.