# Bulk-driven non-equilibrium phase transitions in a mesoscopic ring

Driven diffusive lattice gases have not only been frequently used to model biological transport by molecular motors, but serve also to investigate the intriguing problems of non-equilibrium physics. Two such systems are the total asymmetric exclusion process (TASEP) and the symmetric exclusion process (SEP) that can be regarded as the simplest paradigms of driven (TASEP) and diffusive (SEP) transport.

We have combined both processes into a periodic one-dimensional system and used a mean-field theory and extensive Monte-Carlo simulations for its investigation. The system shows a complex behavior with several non-equilibrium steady states and exhibits bulk-driven phase transitions. We derived a phase diagram in the realm of our mean-field analysis and found interesting correlation effects by comparison to simulations that could be explained phenomenologically.