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Related papers: Defect annihilation and proliferation in active ne…

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To enhance the understanding of the behavior of active nematic, it is important to understand the behavior of topological defects. In this paper, we study the configuration of topological defects of a two-dimensional active nematic around a…

Soft Condensed Matter · Physics 2026-02-16 Hiroki Matsukiyo , Jun-ichi Fukuda

Active materials are those in which individual, uncoordinated local stresses drive the material out of equilibrium on a global scale. Examples of such assemblies can be seen across scales from schools of fish to the cellular cytoskeleton…

Soft Condensed Matter · Physics 2022-09-30 Nitin Kumar , Rui Zhang , Steven A. Redford , Juan J. de Pablo , Margaret L. Gardel

The dynamics of active smectic liquid crystals confined on a spherical surface is explored through an active phase field crystal model. Starting from an initially randomly perturbed isotropic phase, several types of topological defects are…

Soft Condensed Matter · Physics 2025-03-11 Michael Nestler , Simon Praetorius , Zhi-Feng Huang , Hartmut Löwen , Axel Voigt

The motion of topological defects is an important feature of the dynamics of all liquid crystals, and is especially conspicuous in active liquid crystals. Understanding defect motion is a challenging theoretical problem, because the…

Soft Condensed Matter · Physics 2019-01-24 Xingzhou Tang , Jonathan V. Selinger

We provide a comprehensive quantitative analysis of localized and extended topological defects in the steady state of 2D passive and active repulsive Brownian disk systems. We show that, both in and out-of-equilibrium, the passage from the…

The growing interest in active nematics and the emerging evidence of the relevance of topological defects in biology asks for reliable data analysis tools to identify, classify and track such defects in simulation and microscopy data. We…

Soft Condensed Matter · Physics 2020-02-10 Dennis Wenzel , Michael Nestler , Sebastian Reuther , Maximilian Simon , Axel Voigt

Active living matter continuously creates and annihilates topological defects in a process that remains poorly understood. Here, we investigate these dynamics in two distinct active living systems: swarming bacteria and human bronchial…

Topological defects are a ubiquitous phenomenon in diverse physical systems. In nematic liquid crystals (LCs), they are dynamic, physicochemically distinct, sensitive to stimuli, and are thereby promising for a range of applications.…

Soft Condensed Matter · Physics 2023-12-25 Shengzhu Yi , Hao Chen , Xinyu Wang , Miao Jiang , Bo Li , Qi-huo Wei , Rui Zhang

Recent experiments and numerical studies have drawn attention to the dynamics of active nematics. Two-dimensional active nematics flow spontaneously and exhibit spatiotemporal chaotic flows with proliferation of topological defects in the…

Soft Condensed Matter · Physics 2020-07-08 Farzan Vafa , Mark J. Bowick , M. Cristina Marchetti , Boris I. Shraiman

The properties of liquid crystals can be modelled using an order parameter which describes the variability of the local orientation of rod-like molecules. Defects in the director field can arise due to external factors such as applied…

Numerical Analysis · Mathematics 2019-10-08 Craig S. MacDonald , John A. Mackenzie , Alison Ramage

A nematic liquid crystal confined to the surface of a sphere exhibits topological defects of total charge $+2$ due to the topological constraint. In equilibrium, the nematic field forms four $+1/2$ defects, located at the corners of a…

Soft Condensed Matter · Physics 2020-07-22 Yi-Heng Zhang , Markus Deserno , Zhan-Chun Tu

When a nematic liquid crystal is confined in a porous medium with strong anchoring conditions, topological defects, called disclinations, are stably formed with numerous possible configurations. Since the energy barriers between them are…

Soft Condensed Matter · Physics 2015-06-12 Takeaki Araki

How do topological defects affect the degree of order in active matter? To answer this question we investigate an agent-based model of self-propelled particles, which accounts for polar alignment and short-ranged repulsive interactions. For…

Soft Condensed Matter · Physics 2014-04-30 Christoph A. Weber , Christopher Bock , Erwin Frey

We present a novel framework for the study of disclinations in two-dimensional active nematic liquid crystals, and topological defects in general. The order tensor formalism is used to calculate exact multi-particle solutions of the…

Soft Condensed Matter · Physics 2018-02-28 Dario Cortese , Jens Eggers , Tanniemola B. Liverpool

We report on the dynamical behavior of defects of strength s = +/- 1/2 in a lyotropic liquid crystal during the annihilation process. By following their positions using time resolved polarizing microscopy technique, we present statistically…

We study a continuum model of an extensile active nematic to show that mesoscale turbulence develops in two stages: (i) ordered regions undergo an intrinsic hydrodynamic instability generating walls, lines of stong bend deformations, (ii)…

Soft Condensed Matter · Physics 2015-06-18 Sumesh P. Thampi , Ramin Golestanian , Julia M. Yeomans

ATP-driven microtubule-kinesin bundles can self-assemble into two-dimensional active liquid crystals (ALCs) that exhibit a rich creation and annihilation dynamics of topological defects, reminiscent of particle-pair production processes in…

Soft Condensed Matter · Physics 2016-09-21 Anand U. Oza , Jörn Dunkel

Topological defects are increasingly being identified in various biological systems, where their characteristic flow fields and stress patterns are associated with continuous active stress generation by biological entities. Here, using…

Soft Condensed Matter · Physics 2022-11-09 Lasse Bonn , Aleksandra Ardaseva , Romain Mueller , Tyler N. Shendruk , Amin Doostmohammadi

Point-like topological defects are singular configurations that occur in a variety of in and out of equilibrium systems with two-dimensional orientational order. As they are associated with a nonzero circuitation condition, the presence of…

Statistical Mechanics · Physics 2023-07-13 Jacopo Romano , Benoît Mahault , Ramin Golestanian

We study the spatiotemporal patterns that emerge when an active nematic film is topologically constraint. These topological constraints allow to control the non-equilibrium dynamics of the active system. We consider ellipsoidal shapes for…

Soft Condensed Matter · Physics 2017-03-13 Francesco Alaimo , Christian Köhler , Axel Voigt