Virial stress in systems of active Brownian particles in the presence of translational and rotational inertia

Abstract

We elucidate the stress in a system of active Brownian particles augmented with translational and rotational inertia (ABP+TRI). Stress tensors are derived for periodic systems as well as systems confined between walls by employing Lagrange's equations of motion of the first kind for the rotational motion. Using Langevin simulations of an ideal active gas in two dimensions, we confirm the existence of an equation of state for periodic systems that depends on translational and rotational inertia in general. Confinement implies a strong polarization of the propulsion direction near a wall and an enhanced density, both of which increase with increasing rotational inertia. This affects the local stress tensor normal to the confining walls, leading to a breakdown of the equation of state. Yet the local stress in the bulk part of the confined systems is identical with that of the periodic system. Importantly, for both kinds of boundary conditions, the so-called swim stress is not included in the local stress tensor; thus, in general, the swim stress is not representative of the stress in systems of ABP+TRIs.

arXiv comment16 pages, 17 figures

References in corpus (29)

• Active Particles in Complex and Crowded Environments
• The Mechanics and Statistics of Active Matter
• Motility-Induced Phase Separation
• Physics of Microswimmers - Single Particle Motion and Collective Behavior
• Athermal Phase Separation of Self-Propelled Particles with no Alignment
• Meso-scale turbulence in living fluids
• Pressure is not a state function for generic active fluids
• The 2019 Motile Active Matter Roadmap
• Computational models for active matter
• A simple and effective Verlet-type algorithm for simulating Langevin dynamics
• Crystallization in a dense suspension of self-propelled particles
• Inertial effects of self-propelled particles: from active Brownian to active Langevin motion
• Towards a 'Thermodynamics' of Active Matter
• Dynamics of Self-Propelled Particles Under Strong Confinement
• Cooperative Motion of Active Brownian Spheres in Three-Dimensional Dense Suspensions
• Inertial delay of self-propelled particles
• Virial pressure in systems of active Brownian particles
• Ideal bulk pressure of active Brownian particles
• Swim pressure on walls with curves and corners
• On the distribution and swim pressure of run-and-tumble particles in confinement
• Active turbulence in microswimmer suspensions -- the role of active hydrodynamic stress and volume exclusion
• Mechanical pressure and momentum conservation in dry active matter
• Microscopic Origins of the Swim Pressure and the Anomalous Surface Tension of Active Matter
• Stress Tensors of Multiparticle Collision Dynamics Fluids
• Role of rotational inertia for collective phenomena in active matter
• Local stress and pressure in an inhomogeneous system of spherical active Brownian particles
• Polarization-Density Patterns of Active Particles in Motility Gradients
• Computing the local pressure in molecular dynamics simulations
• Collective dynamics of active dumbbells near a circular obstacle