Impact fragmentation of model flocks.
Predicting the bulk material properties of active matter is challenging since these materials are far from equilibrium and standard statistical-mechanics approaches may fail. We report a computational study of the surface properties of a well known active matter system: aggregations of self-propelled particles that are coupled via an orientational interaction and that resemble bird flocks. By simulating the impact of these models flocks on an impermeable surface, we find that they fragment into subflocks with power-law mass distributions, similar to shattering brittle solids but not to splashing liquid drops. Thus, we find that despite the interparticle interactions, these model flocks do not possess an emergent surface tension.
Department of Physics, Yale University, New Haven, Connecticut 06520, USA.
Pearson W
PW
Miller
Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520, USA.
Nicholas T
NT
Ouellette