  Colloidal inclusions suspended in a bath of smaller particles experience an
effective bath-mediated attraction at small intersurface separations, which is
known as the depletion interaction. In an active bath of nonchiral
self-propelled particles, the effective force changes from attraction to
repulsion; an effect that is suppressed, when the active bath particles are
chiral. Using Brownian Dynamics simulations, we study the effects of channel
confinement and bath chirality on the effective forces and torques that are
mediated between two inclusions that may be fixed within the channel or may be
allowed to rotate freely as a rigid dimer around its center of mass. We show
that the confinement has a strong effect on the effective interactions,
depending on the orientation of the dimer relative to the channel walls. The
active particle chirality leads to a force imbalance and, hence, a net torque
on the inclusion dimer, which we investigate as a function of the bath
chirality strength and the channel height.
