Two-species asymmetric exclusion process with site sharing

This letter investigates the two-species asymmetric simple exclusion process (ASEP) with site sharing on a ring. The contribution of this study as compared to previous two-species ASEP models is that the oppositely moving particles do not pass each other by an exchanging mechanism but by sharing a site (characterized by sharing probability q). The model is investigated under random update and with periodic boundary conditions using Monte Carlo simulations and a cluster-based mean-field calculation. In the symmetric case (densities of two-species particles are equal), the simulation results show that there is a plateau in the currentdensity relationship for intermediate particle densities. The plateau corresponds to the maximal current and the plateau region shrinks with the increase of q. In the asymmetric case, the plateau is not observed. For comparison we examine the site-exchanging model which means that two-species particles can exchange their positions with a certain probability. The site-exchanging model does not exhibit such a plateau in the currentdensity relationship.