Liquid-state properties and jamming dynamics of athermal persistent active matter

To investigate the effects of non-thermal particle-scale forcing in dynamic arrest, we have studied, using Langevin simulations, a two-dimensional athermal binary mixture of active Brownian particles with persistent self-propulsion forces. In the limit of infinite persistence time, this system exhibits a jamming transition as the strength of the active force is decreased. The homogeneous liquid state obtained at large values of the active force exhibits unusual properties: the average kinetic energy and the width of the distribution of the kinetic energy increase with increasing system size and a length scale extracted from spatial correlations of the velocity field also increases with system size without showing any sign of saturation. We also investigate how this active liquid approaches a force-balanced jammed state when the self-propulsion force is removed or reduced to a small value. We show that the jamming proceeds via a three-stage relaxation process whose timescale grows with the magnitude of the active force and the system size. We relate the dependence of the jamming time on the system size to the large correlation length obtained from velocity correlations in the liquid state.