Defect binding-unbinding transition in active nematic membranes

Abstract

We investigate the dynamics of active nematic liquid crystals on deformable membranes, focusing on the interplay between active stress and anisotropic curvature coupling. Using a minimal model, we simulate the coupled evolution of the nematic order parameter and membrane height. We demonstrate a continuous transition from a curvature-dominated regime, where topological defects are trapped by local deformation, to an activity-dominated regime exhibiting active turbulence. A scaling analysis reveals that the critical activity threshold ${\zeta }_c$ scales as ${\alpha }^2/\kappa$, where $\alpha$ and $\kappa$ are the coupling constant and bending stiffness, respectively; this relationship is confirmed by our numerical results. Furthermore, we find that significant correlations between the orientational pattern and membrane geometry persist even in the turbulent regime. Specifically, we identify that "walls" in the director field induce characteristic wave-like curvature profiles, providing a mechanism for dynamic coupling between order and shape. These results offer a physical framework for understanding defect-mediated deformation in nonequilibrium biological membranes.

9 pages, 5 figures

References in corpus (26)

• Active Particles in Complex and Crowded Environments
• The Mechanics and Statistics of Active Matter
• Spontaneous motion in hierarchically assembled active matter
• Meso-scale turbulence in living fluids
• Topology and Dynamics of Active Nematic Vesicles
• Topological defect launches 3D mound in the active nematic sheet of neural progenitors
• Anisotropy links cell shapes to tissue flow during convergent extension
• Instabilities and Topological Defects in Active Nematics
• Theory of defect-mediated morphogenesis
• Correlation lengths in hydrodynamic models of active nematics
• Surface free energies for nematic shells
• Statistical Properties of Autonomous Flows in 2D Active Nematics
• Topology and morphology of self-deforming active shells
• Hydrodynamics of Active Defects: from order to chaos to defect ordering
• Effect of cellular rearrangement time delays on the rheology of vertex models for confluent tissues
• Active nematic defects and epithelial morphogenesis
• Active morphogenesis of patterned epithelial shells
• Patterning of morphogenetic anisotropy fields
• Theory of nematic and polar active fluid surfaces
• Computational modeling of active deformable membranes embedded in 3D flows
• Probing active nematics with in-situ microfabricated elastic inclusions
• Mobility Measurements Probe Conformational Changes in Membrane Proteins due to Tension
• Morphodynamics of Active Nematic Fluid Surfaces
• Dynamics of orientational ordering in fluid membranes
• Flow patterns and defect dynamics of active nematics under an electric field
• Spontaneous rotation and propulsion of suspended capsules in active nematics