Effects of inertia on conformation and dynamics of tangentially-driven active filaments

TL;DR

This paper investigates how inertia influences the shape and movement of active filaments, revealing that inertia significantly affects their conformation and diffusion, especially at high activity levels.

Contribution

It introduces a comprehensive analysis of inertial effects on active polymers, combining simulations and analytical calculations to uncover new behaviors not seen in passive or purely overdamped systems.

Findings

Inertia increases the persistence length of active polymers.

Inertia causes enhanced diffusion of the center of mass.

Inertial effects become prominent at high activity levels.

Abstract

Active filament-like systems propelling along their backbone exist across the scales ranging from motor-driven bio-filaments to worms and robotic chains. In macroscopic active filaments such as chain of robots, in contrast to their microscopic counterparts, inertial effects on their motion cannot be ignored. Nonetheless, consequences of interplay between inertia and flexibility on shape and dynamics of active filaments remain unexplored. Here, we examine inertial effects on flexible tangentially-driven active polymer model pertinent to above examples and we determine the conditions under which inertia becomes important. Performing Langevin dynamics simulations of active polymers with underdamped and overdamped dynamics for a wide range of contour lengths and activities, we uncover striking inertial effects on conformation and dynamics at high activities. Inertial collisions increase the persistence length of active polymers and remarkably alter their scaling behavior. In stark contrast to passive polymers, inertia leaves its fingerprint at long times by an enhanced diffusion of the center of mass. We rationalize inertia-induced enhanced dynamics by analytical calculations of center of mass velocity correlations, applicable to any active polymer model, which reveal significant contributions from active force fluctuations convoluted by inertial relaxation.