title: Phase transition in the ABC model.
abstract: Recent studies have shown that one-dimensional driven systems can exhibit phase separation even if the dynamics is governed by local rules. The ABC model, which comprises three particle species that diffuse asymmetrically around a ring, shows anomalous coarsening into a phase separated steady state. In the limiting case in which the dynamics is symmetric and the parameter q describing the asymmetry tends to one, no phase separation occurs and the steady state of the system is disordered. In the present work, we consider the weak asymmetry regime q=exp(-beta/N), where N is the system size, and study how the disordered state is approached. In the case of equal densities, we find that the system exhibits a second-order phase transition at some nonzero beta(c). The value of beta(c)=2pi square root 3 and the optimal profiles can be obtained by writing the exact large deviation functional. For nonequal densities, we write down mean-field equations and analyze some of their predictions.
authors.affiliation: School of Physics, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, UK.
authors.forename: M
authors.initials: M
authors.lastname: Clincy
authors.forename: B
authors.initials: B
authors.lastname: Derrida
authors.forename: M R
authors.initials: MR
authors.lastname: Evans