  The conformational and dynamical properties of active ring polymers are
studied by numerical simulations. The two-dimensionally confined polymer is
modeled as a closed bead-spring chain, driven by tangential forces, put in
contact with a heat bath described by the Brownian multiparticle collision
dynamics. Both phantom polymers and chains comprising excluded volume
interactions are considered for different bending rigidities. The size and
shape are found to be dependent on persistence length, driving force, and bead
mutual exclusion. The lack of excluded volume interactions is responsible for a
shrinkage of active rings when increasing driving force in the flexible limit
while the presence induces a moderate swelling of chains. Internal dynamics of
flexible phantom active rings shows activity-enhanced diffusive behavior at
large activity values while, in the case of self-avoiding active chains, it is
characterized by active ballistic motion not depending on stiffness. The
long-time dynamics of active rings is marked by rotational motion whose period
scales as the inverse of the applied tangential force, irrespective of
persistence length and beads self-exclusion.
