Nonequilibrium tricriticality in one dimension

We show the existence of a nonequilibrium tricritical point induced by a repulsive interaction in one-dimensional asymmetric exclusion processes. The tricritical point is associated with the particle-hole symmetry breaking introduced by the repulsion. The phase diagram and the crossover in the neighbourhood of the tricritical point for the shock formation at one of the boundaries are determined. Copyright (C) EPLA, 2008.