Collective motion of self-trapping chiral active particles induced by a noisy geometric environment.

Abstract

Strategies for trapping and manipulating chiral active matter are crucial in fields ranging from nonequilibrium physics to chemical engineering and biology. While various methods for controlling active matter have been developed, achieving spontaneous trapping and collective manipulation in complex, variable, noisy environments remains an open challenge. In this paper, we investigate the self-trapping effect and collective motion patterns of chiral active particles induced by a noisy geometric environment in the chiral Vicsek-like model (CVLM). The heterogeneous environment relies on designing the topography by varying the spatial noise intensity, featuring a finite noiseless circular region with radius R_{0}. We identify two key conditions for self-trapping behavior: (i) sufficient interaction radius (r) to break symmetry and enable collective motion, and (ii) chirality (ω) that satisfies the geometric constraints, where stable and effective trapping occurs only if ω>ω_{c}, with ω_{c}≃v/R_{0}. We also analyze how different system parameters influence the fraction of trapped particles (FTP). Furthermore, our system reveals a variety of phase transitions driven by the interplay between ω and r. Interestingly, varying ω uncovers additional phases, such as self-reverting vortices, orbital polarization, and vibrational polarization. Additionally, changes in particle interaction r result in three regimes of particle motion: homogeneous disorder, multiple flocks, and single flocks. These findings may inspire innovative strategies for achieving spontaneous trapping and regulating chiral particles in complex environments.