Self-trapping of active particles induced by non-reciprocal interactions in disordered media

Rodrigo Saavedra, Fernando Peruani

Published 2024-04-16Version 1

Disordered media is known to modify the transport properties of active matter depending on interactions between particles and with the substrate. Here we study systems of active particles with visual-like perception that co-align with the positions of perceived conspecifics, and anti-align with positions of static obstacles. We report a novel self-trapping mechanism of particles forming closed loops that progressively shrink, surrounding one or multiple obstacles.This mechanism corresponds to a pinning behavior preventing particle diffusion. Increased co-alignment strength is found to reduce loop shrinking time, although this effect reaches a plateau at higher strengths. Loops are found to initially exhibit local polar order, but eventually they transition to nematic states as they absorb more particles. We show a phase diagram demonstrating self-trapping occurs within a specific range of aperture angles of the vision cone.