title: Unusual shock wave in two-species driven systems with an umbilic point.
abstract: Using dynamical Monte Carlo simulations we observe the occurrence of an unexpected shock wave in driven diffusive systems with two conserved species of particles. This U shock is microscopically sharp, but does not satisfy the usual criteria for the stability of shocks. Exact analysis of the large-scale hydrodynamic equations of motion reveals the presence of an umbilical point which we show to be responsible for this phenomenon. We prove that such an umbilical point is a general feature of multispecies driven diffusive systems with reflection symmetry of the bulk dynamics. We argue that a U shock will occur whenever there are strong interactions between species such that the current-density relation develops a double well and the umbilical point becomes isolated.
authors.affiliation: Max Planck Institute for Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany.
authors.forename: Vladislav
authors.initials: V
authors.lastname: Popkov
authors.forename: Gunter M
authors.initials: GM
authors.lastname: Schütz
mesh_terms: D008962:Models, Theoretical; D009010:Monte Carlo Method; D055585:Physical Phenomena