Insensitivity of active nematic dynamics to topological constraints

Abstract

Confining a liquid crystal imposes topological constraints on the orientational order, allowing global control of equilibrium systems by manipulation of anchoring boundary conditions. In this article, we investigate whether a similar strategy allows control of active liquid crystals. We study a hydrodynamic model of an extensile active nematic confined in containers, with different anchoring conditions that impose different net topological charges on the nematic director. We show that the dynamics are controlled by a complex interplay between topological defects in the director and their induced vortical flows. We find three distinct states by varying confinement and the strength of the active stress: a topologically minimal state, a circulating defect state, and a turbulent state. In contrast to equilibrium systems, we find that anchoring conditions are screened by the active flow, preserving system behavior across different topological constraints. This observation identifies a fundamental difference between active and equilibrium materials.

References in corpus (29)

• The Mechanics and Statistics of Active Matter
• Spontaneous motion in hierarchically assembled active matter
• Meso-scale turbulence in living fluids
• Hydrodynamic fluctuations and instabilities in ordered suspensions of self-propelled particles
• Confinement Stabilizes a Bacterial Suspension into a Spiral Vortex
• Fluid Flows Created by Swimming Bacteria Drive Self-Organization in Confined Suspensions
• Spontaneous flow transition in active polar gels
• Topological colloids
• Orientational order of motile defects in active nematics
• Flocking at a distance in active granular matter
• Transition from turbulent to coherent flows in confined three-dimensional active fluids
• Directed collective motion of bacteria under channel confinement
• Defect dynamics in active nematics
• Stabilization of active matter by flow-vortex lattices and defect ordering
• Onset of meso-scale turbulence in living fluids
• Spontaneous Circulation of Confined Active Suspensions
• Spontaneous division and motility in active nematic droplets
• Vorticity, Defects and Correlations in Active Turbulence
• Spontaneous flow states in active nematics: a unified picture
• Emergence and Persistence of Collective Cell Migration on Small Circular Micropatterns
• Banding, Excitability and Chaos in Active Nematic Suspensions
• Tunable dynamics of microtubule based active isotropic gels
• Confined active nematic flow in cylindrical capillaries
• Correlation lengths in hydrodynamic models of active nematics
• Analytical structure, dynamics, and coarse-graining of a kinetic model of an active fluid
• Active nematic materials with substrate friction
• Polar Patterns in Active Fluids
• Antipolar ordering of topological defects in active liquid crystals
• Phase Separation and Emergent Structures in an Active Nematic

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• The 2019 Motile Active Matter Roadmap
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• Optimal Control of Active Nematics
• Submersed Micropatterned Structures Control Active Nematic Flow, Topology and Concentration
• Vesicle shape transformations driven by confined active filaments
• Twist-induced crossover from 2D to 3D turbulence in active nematics
• Theory of defect motion in 2D passive and active nematic liquid crystals
• Data-driven discovery of active nematic hydrodynamics
• Multiscale Microtubule Dynamics in Active Nematics
• Defect Spirograph: Dynamical Behavior of Defects in Spatially Patterned Active Nematics
• Exact coherent structures and phase space geometry of pre-turbulent 2D active nematic channel flow
• Active Matter Invasion
• Alignment of a topological defect by an activity gradient
• Helical Flow States in Active Nematics
• Spontaneous rotation of active droplets in two and three dimensions
• Vortex Lattices in Active Nematics with Periodic Obstacle Arrays
• Collective Vortical Motion and Vorticity Reversals of Self-Propelled Particles on Circularly Patterned Substrates
• Stability of the interface of an isotropic active fluid
• Friction mediated phase transition in confined active nematics
• Flow patterns and defect dynamics of active nematics under an electric field
• Mechanochemical Topological Defects in an Active Nematic
• Boundaries control active channel flows
• Active Nematic Multipoles: Flow Responses and the Dynamics of Defects and Colloids
• Density-polarity coupling in confined active polar films: asters, spirals, and biphasic orientational phases
• Analytical model for the motion and interaction of two-dimensional active nematic defects
• Machine Learning Forecasting of Active Nematics