Transport of an active particle in an open-wedge channel

Lorenzo Caprini, Fabio Cecconi, Umberto Marini Bettolo Marconi

Published 2019-01-25Version 1

The transport of independent active Brownian particles within a two-dimensional narrow channel, modeled as an open-wedge, is studied both numerically and theoretically. We show that the active force tends to localize the particles near the walls thus reducing the effect of the entropic force which, instead, is prevailing in the case of passive particles. As a consequence, the exit of active particles from the smaller side of the channel is facilitated with respect to their passive counterpart. By continuously re-injecting particles in the middle of the wedge we obtain a steady regime whose properties are investigated with and without the presence of an external constant driving field. We characterize the statistics and properties of the exit process form the two opposite sides of the channel, also by making a comparison between the active and passive case. Our study reveals the existence of an optimal value of the persistence time of the active force which is able to guarantee the maximal efficiency in the transport process.