DRIFTING SPATIAL STRUCTURES IN A SYSTEM WITH OPPOSITELY DRIVEN SPECIES

A system consisting of two conservative, oppositely driven species of particles with excluded volume interaction alone is studied on a torus . ?he system undergoes a phase transition between homogeneous and inho mogeneous phases, as the particle densities are varied. Focusing on th e inhomogeneous phase with generally unequal numbers of the two specie s, the spatial structure is found to drift counterintuitively against the majority species at a constant velocity that depends on the extern al field, system size, and particle densities. Such dependences are de rived from a coarse-grained continuum theory, and a microscopic mechan ism for the drift is explained. With virtually no tuning parameter, va rious theoretical predictions, notably a field-system-size scaling, ag ree extremely well with the simulations.