Dynamics of a homogeneous active dumbbell system

Abstract

We analyse the dynamics of a two dimensional system of interacting active dumbbells. We characterise the mean-square displacement, linear response function and deviation from the equilibrium fluctuation-dissipation theorem as a function of activity strength, packing fraction and temperature for parameters such that the system is in its homogeneous phase. While the diffusion constant in the last diffusive regime naturally increases with activity and decreases with packing fraction, we exhibit an intriguing non-monotonic dependence on the activity of the ratio between the finite density and the single particle diffusion constants. At fixed packing fraction, the time-integrated linear response function depends non-monotonically on activity strength. The effective temperature extracted from the ratio between the integrated linear response and the mean-square displacement in the last diffusive regime is always higher than the ambient temperature, increases with increasing activity and, for small active force it monotonically increases with density while for sufficiently high activity it first increases to next decrease with the packing fraction. We ascribe this peculiar effect to the existence of finite-size clusters for sufficiently high activity and density at the fixed (low) temperatures at which we worked. The crossover occurs at lower activity or density the lower the external temperature. The finite density effective temperature is higher (lower) than the single dumbbell one below (above) a cross-over value of the Peclet number.

To be published in Physical Review E

References in corpus (23)

• Novel type of phase transition in a system of self-driven particles
• Self-motile colloidal particles: from directed propulsion to random walk
• Meso-scale turbulence in living fluids
• Statistical Mechanics of Interacting Run-and-Tumble Bacteria
• Phase transition in the collective migration of tissue cells: experiment and model
• Diffusive transport without detailed balance in motile bacteria: Does microbiology need statistical physics?
• Non-equilibrium clustering of self-propelled rods
• Collective motion and nonequilibrium cluster formation in colonies of gliding bacteria
• Sedimentation, trapping, and rectification of dilute bacteria
• A self-propelled particle in an external potential: is there an effective temperature?
• Minimal model for active nematics: quasi-long-range order and giant fluctuations
• Spontaneously ordered motion of self-propelled particles
• Swarm behavior of self-propelled rods and swimming flagella
• Shearing active gels close to the isotropic-nematic transition
• Self-Propelled Rods near Surfaces
• Effective Temperature of Red Blood Cell Membrane Fluctuations
• Clustering and heterogeneous dynamics in a kinetic Monte-Carlo model of self-propelled hard disks
• Effective temperature and glassy dynamics of active matter
• Dumb-bell swimmers
• Biased swimming cells do not disperse in pipes as tracers: a population model based on microscale behaviour
• Dispersion of biased swimming microorganisms in a fluid flowing through a tube
• Asymmetric exclusion processes with constrained dynamics
• CUDA simulations of active dumbbell suspensions

Cited by in corpus (8)

• Motility-induced phase separation and coarsening in active matter
• Small activity differences drive phase separation in active-passive polymer mixtures
• Large fluctuations and dynamic phase transition in a system of self-propelled particles
• Effective temperatures in inhomogeneous passive and active bidimensional Brownian particle systems
• Morphology and flow patterns in highly asymmetric active emulsions
• Chaotic and periodical dynamics of active chiral droplets
• Stochastic dynamics of collective modes for Brownian dipoles
• Recovery of mechanical pressure in a gas of underdamped active dumbbells with Brownian noise