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

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.