Transport coefficients of self-propelled particles: Reverse perturbations and transverse current correlations
arXiv:1905.04082 · doi:10.1103/PhysRevE.100.042603
Abstract
The reverse perturbation method [Phys. Rev. E 59, 4894 (1999)] for shearing simple liquids and measuring their viscosity is extended to the Vicsek-model (VM) of active particles [Phys. Rev. Lett. 75, 1226 (1995)] and its metric-free version. The sheared systems exhibit a phenomenon that is similar to the skin effect of an alternating electric current: momentum that is fed into the boundaries of a layer decays mostly exponentially towards the center of the layer. It is shown how two transport coefficients, i.e. the shear viscosity and the momentum amplification coefficient , can be obtained by fitting this decay with an analytical solution of the hydrodynamic equations for the VM. The viscosity of the VM consists of two parts, a kinetic and a collisional contribution. While analytical predictions already exist for the former, a novel expression for the collisional part is derived by an Enskog-like kinetic theory. To verify the predictions for the transport coefficients, Green-Kubo relations were evaluated and transverse current correlations were measured in independent simulations. Not too far to the transition to collective motion, we find excellent agreement between the different measurements of the transport coefficients. However, the measured values of and are always slightly higher than the mean-field predictions, even at large mean free paths and at state points quite far from the threshold to collective motion, that is, far in the disordered phase. These findings seem to indicate that the mean-field assumption of molecular chaos is much less reliable in systems with velocity-alignment rules such as the VM, compared to models obeying detailed balance such as Multi-Particle Collision Dynamics.
References in corpus (48)
- Novel type of phase transition in a system of self-driven particles
- Collective motion
- Interaction Ruling Animal Collective Behaviour Depends on Topological rather than Metric Distance: Evidence from a Field Study
- Flocks, herds, and schools: A quantitative theory of flocking
- Scale-free correlations in bird flocks
- Collective motion of self-propelled particles interacting without cohesion
- Boltzmann and hydrodynamic description for self-propelled particles
- Hydrodynamics determines collective motion and phase behavior of active colloids
- Hydrodynamic equations for self-propelled particles: microscopic derivation and stability analysis
- Pattern formation in self-propelled particles with density-dependent motility
- Spontaneously ordered motion of self-propelled particles
- Enhanced diffusion and ordering of self-propelled rods
- Transport coefficients of a mesoscopic fluid dynamics model
- Relevance of Metric-Free Interactions in Flocking Phenomena
- Hydrodynamics of self-propelled hard rods
- From Phase to Micro-Phase Separation in Flocking Models: The Essential Role of Non-Equilibrium Fluctuations
- Nonequilibrium equation of state in suspensions of active colloids
- Revisiting the flocking transition using active spins
- Simulation of Claylike Colloids
- Kinetic Theory of Flocking: Derivation of Hydrodynamic Equations
- A Reanalysis of the Hydrodynamic Theory of Fluid, Polar-Ordered Flocks
- A mean-field theory for self-propelled particles interacting by velocity alignment mechanisms
- New aspects of the continuous phase transition in the scalar noise model (SNM) of collective motion
- Simple and faithful nonlinear field equations for aligning self-propelled rods
- Boltzmann-Ginzburg-Landau approach for continuous descriptions of generic Vicsek-like models
- Transport Coefficients for Stochastic Rotation Dynamics in Three Dimensions
- Transport coefficients of off-lattice mesoscale-hydrodynamics simulation techniques
- Collective dynamics of self-propelled particles with variable speed
- Continuous theory of active matter systems with metric-free interactions
- Invasion-wave induced first-order phase transition in systems of active particles
- Efficient mesoscale hydrodynamics: multiparticle collision dynamics with massively parallel GPU acceleration
- Equilibrium calculation of transport coefficients for a fluid-particle model
- Self-propelled particles with selective attraction-repulsion interaction - From microscopic dynamics to coarse-grained theories
- Phase transitions in swarming systems: A recent debate
- Kinetic theory for systems of self-propelled particles with metric-free interactions
- Critical Phenomenon of the Order-Disorder Transition in Incompressible Flocks
- Understanding Collective Dynamics of Soft Active Colloids by Binary Scattering
- Comparison between Smoluchowski and Boltzmann approaches for self-propelled rods
- Giant Kovacs-Like Memory Effect for Active Particles
- Consensus of self-driven agents with avoidance of collisions
- Chapman-Enskog expansion for the Vicsek model of self-propelled particles
- A Critical Assessment of the Boltzmann Approach for Active Systems
- Towards a quantitative kinetic theory of polar active matter
- Active matter beyond mean-field: Ring-kinetic theory for self-propelled particles
- The microscopic phase density functional approach to the construction of the kinetic and hydrodynamic description for the system of self-propelled particles
- Comment on Ihle, "Towards a quantitative kinetic theory of polar active matter"
- Discussion on Peshkov et al., "Boltzmann-Ginzburg-Landau approach for continuous descriptions of generic Vicsek-like models"
- Reply to comment on "Towards a quantitative kinetic theory of polar active matter" by Bertin et al