  We numerically examine the transport of an assembly of active run-and-tumble
disks interacting with a traveling wave substrate. We show that as a function
of substrate strength, wave speed, disk activity, and disk density, a variety
of dynamical phases arise that are correlated with the structure and net flux
of disks. We find that there is a sharp transition into a state where the disks
are only partially coupled to the substrate and form a phase separated cluster
state. This transition is associated with a drop in the net disk flux and can
occur as a function of the substrate speed, maximum substrate force, disk run
time, and disk density. Since variation of the disk activity parameters
produces different disk drift rates for a fixed traveling wave speed on the
substrate, the system we consider could be used as an efficient method for
active matter species separation. Within the cluster phase, we find that in
some regimes the motion of the cluster center of mass is in the opposite
direction to that of the traveling wave, while when the maximum substrate force
is increased, the cluster drifts in the direction of the traveling wave. This
suggests that swarming or clustering motion can serve as a method by which an
active system can collectively move against an external drift.
