We explore the emergence of nonequilibrium collective motion in disordered nonthermal active matter when persistent and crowding effects compete, using simulations a two-dimensional model size polydisperse self-propelled particles. In stark contrast with monodisperse systems, we find that polydispersity stabilizes homogeneous liquid at arbitrary large persistence times, characterized by remarkable velocity correlations irregular turbulent flows. For all values, fluid undergoes glass...

We study two models of overdamped self-propelled disks in dimensions, with and without aligning interactions. Both support active mesoscale flows, leading to chaotic advection transport over large length scales their homogeneous dense fluid states, away from dynamical arrest. They form streams vortices reminiscent multiscale flow patterns turbulence. show that the characteristics these flows do not depend on specific details fluids, result competition between crowding effects persistent...

For tissues to spread, they must be deformable while maintaining their structural integrity. How these opposing requirements are balanced within spreading is not yet well understood. Here, we show that keratin intermediate filaments function in epithelial by adapting tissue mechanical resilience the stresses arising during process. By analysing expansion of enveloping cell layer (EVL) over large yolk early zebrafish embryos vivo, found network maturation EVL cells promoted building up...

<title>Abstract</title> For tissues to spread, they must be deformable while maintaining their structural integrity. How these opposing requirements are balanced within spreading is not yet well understood. Here, we show that keratin intermediate filaments function in epithelial by adapting tissue mechanical resilience the stresses arising during process. By analysing expansion of enveloping cell layer (EVL) over large yolk early zebrafish embryos vivo, found network maturation EVL cells...

We analyze collective motion that occurs during rare (large deviation) events in systems of active particles, both numerically and analytically. discuss the associated dynamical phase transition to motion, which when work is biased towards larger values, with alignment particles' orientations. A finite biasing field needed induce spontaneous symmetry breaking, even large systems. Particle computed exactly for a system two particles. For many-particle systems, we breaking by an...

We use numerical simulations to study the dynamics of dense assemblies self-propelled particles in limit extremely large, but finite, persistence times.

We numerically simulate the uniform athermal shearing of bidisperse, frictionless, two-dimensional spherocylinders and three-dimensional prolate ellipsoids. focus on orientational ordering particles as an asphericity parameter α→0 approach spherical. find that nematic order S_{2} is nonmonotonic in packing fraction ϕ that, α→0, stays finite at jamming above. The to spherical thus appears be singular. also sheared continue rotate above particle contacts preferentially lie along narrowest...

We study two models of overdamped self-propelled disks in dimensions, with and without aligning interactions. Active mesoscale flows leading to chaotic advection emerge both the homogeneous dense fluid away from dynamical arrest, forming streams vortices reminiscent multiscale flow patterns turbulence. show that characteristics these do not depend on specific details active fluids, result competition between crowding effects persistent propulsions. Our results suggest fluids present a type...

In two-dimensional tissues, such as developing germ layers, pair-wise forces (or active stresses) arise from the contractile activity of cytoskeleton, with dissipation provided by three-dimensional surroundings. We show analytically how these stochastic forces, unlike particle-wise independent fluctuating usually considered in matter systems, produce conserved centre-of-mass dynamics and so are able to damp large-wavelength displacement fluctuations elastic systems. A consequence this is...

We present a detailed study of cooperative and correlated dynamics in 2D model system for soft active matter that undergoes motility-induced phase separation (MIPS). Particle displacement correlation functions reveal increasing dynamical heterogeneity with activity. In the phase-separated regime as well truly glassy phase, transverse mean squared displacements shear strain correlations exhibit long-range behaviour decaying r −2 on time scales short compared to rotational diffusion time....

We study shear-driven jamming of ellipsoidal particles at zero temperature with a focus on the microscopic dynamics. find that change from spherical to ellipsoids aspect ratio $\ensuremath{\alpha}=1.02$ gives dramatic changes dynamics much lower translational velocities and new role for rotations. Whereas velocity difference contacts---and thereby dissipation---in collections spheres is dominated by reduced rotations, same quantity in instead totally rotational velocities. By also examining...

We use numerical simulations to study the dynamics of dense assemblies self-propelled particles in limit extremely large, but finite, persistence times. In this limit, system evolves intermittently between mechanical equilibria where active forces balance interparticle interactions. develop an efficient strategy allowing us resolve statistical properties elastic and plastic relaxation events caused by activity-driven fluctuations. The relaxes via a succession scale-free broadly distributed...