Structural dynamics and optimal transport of an active polymer

We study the spontaneous configuration transitions of an active semi-flexible polymer between {\it spiral} and {\it non-spiral} states, and show that the configuration dynamics is fully described by a {\it subcritical pitchfork} bifurcation. Exploiting the fact that active polymer barely moves in {\it spiral} states and exhibits net displacements in {\it non-spiral} states, we theoretically prove that the motion of the active polymer is consistent with a {\it run-and-tumble}-like dynamics. Moreover, we find that there exists an {\it optimal} self-propelling {\it force}, at which the probabilities of finding the polymer in the {\it spiral} and {\it non-spiral} state become equal, that maximizes the diffusion coefficient.