Extreme Active Matter at High Densities
Abstract
Extreme active matter, consisting of self-propelled particles characterized by large persistence time τp and high Péclet number, exhibits remarkable behavior at high densities. In the limit τp -> ∞, the fluid jams as the self-propulsion force f is decreased below a critical value f*(∞). The system is stuck at a force-balanced configuration for f < f*(∞), with stresses concentrated along force chains. For large but finite τp, the approach to dynamical arrest at low f goes through a phase characterized by intermittency in kinetic and potential energy. This intermittency is a consequence of long periods of jamming separated by bursts of plastic yielding associated with Eshelby deformations akin to those found in the response of dense granular materials to an externally imposed shear. In the vicinity of the boundary between the intermittent and ''normal'' fluid phases, correlated plastic events result in large-scale vorticity and turbulent motion. Thus, dense extreme active matter brings together the physics of glass, jamming, plasticity and turbulence, in a new state of driven classical matter.
This work was supported in part by the Department of Science and Technology, India and the Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Bangalore.- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- 2019
- Bibcode:
- 2019APS..MARH61013D