Phase segregation and transport in a two-species multi-lane system

We present a two-channel driven lattice gas model with oppositely directed species moving on two parallel lanes with lane switching processes. We study the correlated lane switching mechanism for particles so that switching may occur with finite probability only when oppositely directed species meet on the same channel. The system is analyzed for a closed ring with conserved total particle number. For asymmetric particle exchange between the lanes, the system exhibits a unique polarization phenomenon with segregation of oppositely directed species between the two lanes. The polarization phenomenon can be understood as a consequence of the existence of an absorbing steady state. For symmetric exchange rate of particles between the lanes, the system remains unpolarized, with equal particle density on both the lanes in the thermodynamic limit of large system size. We study the system using a combination of a mean field (MF) analysis and Monte Carlo simulations. The nature of phase segregation that we see for this system is distinct from driven particle systems which are in contact with the particle reservoir. The features observed for this minimal model will have ramifications for biofilament based intracellular transport, wherein cellular cargoes, e.g. organelles and vesicles, are transported by oppositely directed particles on multiple filament tracks.