The low noise phase of a 2d active nematic

Abstract

We consider a collection of self-driven apolar particles on a substrate that organize into an active nematic phase at sufficiently high density or low noise. Using the dynamical renormalization group, we systematically study the 2d fluctuating ordered phase in a coarse-grained hydrodynamic description involving both the nematic director and the conserved density field. In the presence of noise, we show that the system always displays only quasi-long ranged orientational order beyond a crossover scale. A careful analysis of the nonlinearities permitted by symmetry reveals that activity is dangerously irrelevant over the linearized description, allowing giant number fluctuations to persist though now with strong finite-size effects and a non-universal scaling exponent. Nonlinear effects from the active currents lead to power law correlations in the density field thereby preventing macroscopic phase separation in the thermodynamic limit.

17 pages, 5 figures

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Cited by in corpus (28)

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• Hydrodynamics of Active Defects: from order to chaos to defect ordering
• Emergence of dynamic vortex glasses in disordered polar active fluids
• Hydrodynamic Theory of Flocking in the Presence of Quenched Disorder
• Active Matter Class with Second-Order Transition to Quasi-Long-Range Polar Order
• Chiral active hexatics: Giant number fluctuations, waves and destruction of order
• The role of fluid flow in the dynamics of active nematic defects
• Molecular-scale substrate anisotropy and crowding drive long-range nematic order of cell monolayers
• Polar Fluctuations Lead to Extensile Nematic Behavior in Confluent Tissues
• Designing, Synthesizing and Modeling Active Fluids
• Moving, reproducing, and dying beyond Flatland: Malthusian flocks in dimensions $d>2$
• Isotropic-nematic transition of self-propelled rods in three dimensions
• Long-Range Nematic Order in Two-Dimensional Active Matter
• Universal properties of repulsive self-propelled particles and attractive driven particles
• Giant number fluctuations in dry active polar fluids: A shocking analogy with lightning rods
• Dynamical Sub-classes of Dry Active Nematics
• Fluctuation-induced dynamics of nematic topological defects
• Nematic Torques in Scalar Active Matter: when Fluctuations Favor Polar Order and Persistence
• Quantifying nematic order in evaporation-driven self-assembly of Halloysite nanotubes: Nematic islands and critical aspect ratio
• Alignment Destabilizes Crystal Orders in Active Systems
• Swarming bottom feeders: Flocking at solid-liquid interfaces
• Hydrodynamic theory of flocking at a solid-liquid interface: long range order and giant number fluctuations
• Dry, aligning, dilute, active matter: A synthetic and self-contained overview
• Anti-hyperuniform Critical States of Active Topological Defects
• Bubble formation in active binary mixture model
• Spontaneous flow created by active topological defects
• Pseudo-giant number fluctuations and nematic order in microswimmer suspensions
• On the temperature of an active nematic