Dynamics of an active semi-flexible filament in a spherical cavity

Abstract

We perform numerical simulations of active semiflexible filaments inside a rigid spherical cavity. We study the problem as a function of the bending rigidity, degree of confinement, and strength of the active forces. For passive filaments, the multispool conformations already established in previous studies are recovered, yet even small amounts of activity, when aligned along the direction of the filament backbone, destabilize these passive conformations. What emerges from our study is a highly dynamic scenario, where a filament is capable of escaping local and global energy minima and sample, in a quasiperiodic fashion, an ensemble of conformations usually associated with higher bending energies, and previously observed for passive filaments only under very different degrees of confinement or identified as glassy metastable states. We detail the structural properties of the different states and uncover a new dynamic pathway associated with their formation.