The importance of being discrete -- An agent-based model for active nematics and more

Abstract

We propose an agent-based model of active flexible rods. Inspired by cytoskeletal flows, we introduce activity by an internal flow that contributes to the dissipative forces. The active force between our agents is central and reciprocal, ensuring linear and angular momentum conservation. For nematic activity, we find spontaneous, thresholdless flows and stochastic flow-reorientation, which is accompanied by the formation of topological defects. Defects appear and vanish with activity-dependent rates, and $+1/2$-defects self-propel. These hallmarks of active turbulence are present even on the scale of individual agents. The particle-based interactions lead to an emergent coupling between density and orientation that generates density dipoles around $+1/2$-defects. Finally, we highlight the versatility of our agent-based model by presenting spontaneous flows in three dimensions and tissue growth. Our framework opens the way for an integrated description of living materials, including several forms of activity in the same system.

References in corpus (25)

• Novel type of phase transition in a system of self-driven particles
• Spontaneous motion in hierarchically assembled active matter
• Statistical Mechanics of Interacting Run-and-Tumble Bacteria
• Topological defect launches 3D mound in the active nematic sheet of neural progenitors
• Spontaneous flow transition in active polar gels
• Defect annihilation and proliferation in active nematics
• Orientational order of motile defects in active nematics
• Steady-state hydrodynamic instabilities of active liquid crystals: Hybrid lattice Boltzmann simulations
• Active Turbulence
• Self-Propelled Rods: Insights and Perspectives for Active Matter
• Collective Langevin Dynamics of Flexible Cytoskeletal Fibers
• Defect dynamics in active nematics
• How would you integrate the equations of motion in dissipative particle dynamics simulations?
• Velocity Correlations in an Active Nematic
• Self-organized dynamics and the transition to turbulence of confined active nematics
• Excitable Patterns in Active Nematics
• Dynamics of defects in active nematics
• Hydrodynamics of Active Defects: from order to chaos to defect ordering
• Quantifying material properties of cell monolayers by analyzing integer topological defects
• Patterning of morphogenetic anisotropy fields
• Multi-Particle Collision Dynamics Algorithm for Nematic Fluids
• Towards the cellular-scale simulation of motor-driven cytoskeletal assemblies
• Mesoscopic Simulations of Active-Nematics
• Emergence of epithelial cell density waves
• Density-polarity coupling in confined active polar films: asters, spirals, and biphasic orientational phases