  The conformational and dynamical properties of isolated semiflexible active
polar ring polymers are investigated analytically. A ring is modeled as
continuous Gaussian polymer exposed to tangential active forces. The analytical
solution of the linear non-Hermitian equation of motion in terms of an
eigenfunction expansion shows that ring conformations are independent of
activity. In contrast, activity strongly affects the internal ring dynamics and
yields characteristic time regimes, which are absent in passive rings. On
intermediate time scales, flexible rings show an activity-enhanced diffusive
regime, while semiflexible rings exhibit ballistic motion. Moreover, a second
active time regime emerges on longer time scales, where rings display a
snake-like motion, which is reminiscent to a tank-treading rotational dynamics
in shear flow, dominated by the mode with the longest relaxation time.
