Effect of trapping perturbation on the collective dynamics of self-propelled particles

Department of Physics, Indian Institute of Technology Guwahati - Guwahati-781039, Assam, India

^(a) santra@iitg.ac.in (corresponding author)

Received: 24 April 2021
Accepted: 20 August 2021

Abstract

Collective dynamics of self-propelled particles (SPPs) with inherent perturbation in the system is modelled, incorporating a trapping perturbation in the Vicsek model (VM). Under this perturbation, the particles get trapped for a while with a position-dependent trapping probability as they pass through the trapping region and pick up a random velocity direction on release. The effect of the perturbation on the VM is studied, varying the scalar noise η and the perturbation strength α. The system's response is obtained at two different velocities , and for several systems of sizes L with a specific density . The formation of the travelling band and discontinuous order-disorder transition in the VM is known to occur above a crossover system size . The perturbation in the VM can destroy the travelling band up to a specific system size beyond . Consequently, the value of the crossover size has increased to a higher value . Below , the transition is continuous with the same critical exponents of the VM, and above , the transition is discontinuous. It seems that the VM, even in the presence of inherent perturbation, will always exhibit a discontinuous transition in the asymptotic limit.