Shear Induced Orientational Ordering in Active Glass

Abstract

Dense assemblies of self propelled particles, also known as active or living glasses are abundantaround us, covering different length and time scales: from the cytoplasm to tissues, from bacterialbio-films to vehicular traffic jams, from Janus colloids to animal herds. Being structurally disorderedas well as strongly out of equilibrium, these systems show fascinating dynamical and mechanicalproperties. Using extensive molecular dynamics simulation and a number of different dynamicaland mechanical order parameters we differentiate three dynamical steady states in a sheared modelactive glassy system: (a) a disordered phase, (b) a propulsion-induced ordered phase, and (c) ashear-induced ordered phase. We supplement these observations with an analytical theory based onan effective single particle Fokker-Planck description to rationalise the existence of the novel shear-induced orientational ordering behaviour in our model active glassy system that has no explicitaligning interactions,e.g.of Vicsek-type. This ordering phenomenon occurs in the large persistencetime limit and is made possible only by the applied steady shear. Using a Fokker-Planck descriptionwe make testable predictions without any fit parameters for the joint distribution of single particleposition and orientation. These predictions match well with the joint distribution measured fromdirect numerical simulation. Our results are of relevance for experiments exploring the rheologicalresponse of dense active colloids and jammed active granular matter systems.

8 pages, 5 figures

References in corpus (16)

• Novel type of phase transition in a system of self-driven particles
• Pressure and Phase Equilibria in Interacting Active Brownian Spheres
• A self-propelled particle in an external potential: is there an effective temperature?
• Towards a 'Thermodynamics' of Active Matter
• Spontaneous velocity alignment in Motility-induced Phase Separation
• Multidimensional Stationary Probability Distribution for Interacting Active Particles
• Shearing active gels close to the isotropic-nematic transition
• Motility-Induced Microphase and Macrophase Separation in a Two-Dimensional Active Brownian Particle System
• Perspective: Nonequilibrium glassy dynamics in dense systems of active particles
• Sheared active fluids: thickening, thinning and vanishing viscosity
• Self-Organized Critical Coexistence Phase in Repulsive Active Particles
• Active glasses
• Multiple Types of Aging in Active Glass
• Shear flow induced isotropic to nematic transition in a suspension of active filaments
• Thermally activated flow in models of amorphous solids
• Tractable nonlinear memory functions as a tool to capture and explain dynamical behaviours

Cited by in corpus (5)

• Yielding and plasticity in amorphous solids
• Intermittent relaxation and avalanches in extremely persistent active matter
• Fluid-Glass-Jamming Rheology of Soft Active Brownian Particles
• Bringing together two paradigms of non-equilibrium: Fragile versus robust aging in driven glassy systems
• Tuning Steady Shear Rheology through Active Dopants