Active particle dynamics beyond the jamming density

Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology van der Maasweg 9, Delft, The Netherlands

^(a) t.idema@tudelft.nl

Received: 31 August 2018
Accepted: 23 January 2019

Abstract

Many biological systems form colonies at high density. Passive granular systems will be jammed at such densities, yet for the survival of biological systems it is crucial that they are dynamic. We construct a phase diagram for a system of active particles interacting via Vicsek alignment, and vary the density, self-propulsion force, and orientational noise. We find that the system exhibits four different phases, characterized by transitions in the effective diffusion constant and in the orientational order parameter. Our simulations show that there exists an optimal noise such that particles require a minimal force to unjam, allowing for rearrangements.