Symmetry breaking and phase coexistence in a driven diffusive two-channel system - art. no. 026126

We consider classical hard-core particles moving on two parallel chains in the same direction. An interaction between the channels is included via the hopping rates. For a ring, the stationary state has a product form. For th e case of coupling to two reservoirs, it is investigated analytically and n umerically. In addition to the known one-channel phases, two new regions ar e found, in particular one, where the total density is fixed, but the filli ng of the individual chains changes back and forth, with a preference for s trongly different densities. The corresponding probability distribution is determined and shown to have a universal form. The phase diagram and genera l aspects of the problem are discussed.