Reorientation dynamics in simulated pair-interactions of flexible, penetrable, active filaments

Recent gliding assay experiments on microtubules and actin show that long-range ordered (LRO) active nematic phases of self-propelled filaments can emerge through a combination of collision-induced alignment and crossover events. To gain understanding about how this LRO arises from microscopic interactions, we employ Brownian dynamics simulations of flexible, self-propelled bead-spring chains with a finite energetic penalty for overlap, which permits crossovers when the incident angle of collision is sufficiently large. The interactions in our model contain no aligning potentials; rather, we show how alignment emerges from isotropic interactions between the beads of neighboring active chains. Our results indicate that the reorientation of filament pairs is highly sensitive to their incident angle, their bending rigidity, and their penetrability.