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Related papers: Defect self-propulsion in active nematic films wit…

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We present a hydrodynamic model for a thin spherical shell of active nematic liquid crystal with an arbitrary configuration of defects. The active flows generated by defects in the director lead to the formation of stable vortices,…

Soft Condensed Matter · Physics 2017-11-13 Diana Khoromskaia , Gareth P. Alexander

Colloidal inclusions in nematic fluids induce topological defects that govern their dynamics. These defects create well-understood rheological behavior in passive nematics, but the interplay between colloid-associated defects and…

Soft Condensed Matter · Physics 2025-03-26 Timofey Kozhukhov , Benjamin Loewe , Kristian Thijssen , Tyler N. Shendruk

Topological defects are one of the most conspicuous features of liquid crystals. In two dimensional nematics, they have been shown to behave effectively as particles with both, charge and orientation, which dictate their interactions. Here,…

Soft Condensed Matter · Physics 2021-07-14 Daniel J. G. Pearce , Karsten Kruse

Topological defects are at the root of the large-scale organization of liquid crystals. In two-dimensional active nematics, two classes of topological defects of charges $\pm 1/2$ are known to play a major role due to active stresses.…

Soft Condensed Matter · Physics 2022-04-08 Louis Brézin , Thomas Risler , Jean-François Joanny

Active processes drive and guide biological dynamics across scales -- from subcellular cytoskeletal remodelling, through tissue development in embryogenesis, to population-level bacterial colonies expansion. In each of these, biological…

Inspired by recent experiments that highlight the role of nematic defects in the morphogenesis of epithelial tissues, we develop a minimal framework to study the dynamics of an active curved surface driven by its nematic texture. Allowing…

Soft Condensed Matter · Physics 2022-09-14 Farzan Vafa , L. Mahadevan

As a method for controlling active materials, researchers have suggested designing patterns of activity on a substrate, which should guide the motion of topological defects. To investigate this concept, we model the behavior of a single…

Soft Condensed Matter · Physics 2021-02-10 Xingzhou Tang , Jonathan V. Selinger

Nematic liquid crystals can dramatically reconfigure under dynamic forcing, providing exciting opportunities in active matter. Here, we study a hybrid disk colloid rotated by an external field which generates a dynamic companion topological…

Soft Condensed Matter · Physics 2026-05-26 Qi Xing Zhang , Claire Dore , Mojtaba Rajabi , Edward B. Steager , Kathleen J. Stebe

Engineering synthetic materials that mimic the remarkable complexity of living organisms is a fundamental challenge in science and technology. We study the spatiotemporal patterns that emerge when an active nematicfilm of microtubules and…

Non-equilibrium dynamics of topological defects can be used as a fundamental propulsion mechanism in microscopic active matter. Here, we demonstrate swimming of topological defect-propelled colloidal particles in (passive) nematic fluids…

Soft Condensed Matter · Physics 2021-09-30 Tianyi Yao , Žiga Kos , Yimin Luo , Edward B. Steager , Miha Ravnik , Kathleen J. Stebe

We investigate similarities in the micro-structural dynamics between externally driven and actively driven nematics. Walls, lines of strong deformations in the director field, and topological defects are characteristic features of an active…

Soft Condensed Matter · Physics 2015-04-28 Sumesh P. Thampi , Ramin Golestanian , Julia M. Yeomans

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

Active fluids, such as cytoskeletal filaments, bacterial colonies and epithelial cell layers, exhibit distinctive orientational coherence, often characterized by nematic order and topological defects. By contrast, little is known about…

Soft Condensed Matter · Physics 2021-04-07 Mattia Serra , Linnea Lemma , Luca Giomi , Zvonimir Dogic , L. Mahadevan

Topological defects play a central role in the formation and organization of various biological systems. Historically, such nonequilibrium defects have been mainly studied in the context of homogeneous active nematics. Phase-separated…

Soft Condensed Matter · Physics 2023-07-13 Timo Krüger , Ivan Maryshev , Erwin Frey

Active nematics are fluids in which the components have nematic symmetry and are driven out of equilibrium due to the microscopic generation of an active stress. When the active stress is high, it drives flows in the nematic and can lead to…

Soft Condensed Matter · Physics 2025-11-10 Daniel J. G. Pearce , Berta Martínez-Prat , Jordi Ignés-Mullol , Francesc Sagués

Using agent-based simulations of self-propelled particles subject to short-range repulsion and nematic alignment we explore the dynamical phases of a dense active material confined to the surface of a sphere. We map the dynamical phase…

Soft Condensed Matter · Physics 2018-04-25 Silke Henkes , M. Cristina Marchetti , Rastko Sknepnek

Stabilizing defects in liquid-crystal systems is crucial for many physical processes and applications ranging from functionalizing liquid-crystal textures to recently reported command of chaotic behaviors of active matters. In this work, we…

Soft Condensed Matter · Physics 2017-06-29 Xiuqing Duan , Zhenwei Yao

We study the dynamics of active nematic films on a substrate driven by active flows with or without the incompressible constraint.Through simulations and theoretical analysis, we show that arch patterns are stable in the compressible case,…

Soft Condensed Matter · Physics 2022-11-30 Supavit Pokawanvit , Zhitao Chen , Zhihong You , Luiza Angheluta , M. Cristina Marchetti , Mark J. Bowick

In pulsating active matter, topological defects are motile despite the absence of any macroscopic flows and microscopic self-propulsion. We reveal that this motility arises from a ratchet effect: the mechanochemical coupling between local…

Soft Condensed Matter · Physics 2026-05-26 Luca Casagrande , Alessandro Manacorda , Etienne Fodor

Polar active matter of self-propelled particles sustain spontaneous flows through the full-integer topological defects. We study theoretically the effect of both polar and dipolar active forces on the flow profile around $\pm 1$ defects and…

Soft Condensed Matter · Physics 2023-03-14 Jonas Rønning , Julian Renaud , Amin Doostmohammadi , Luiza angheluta