Chaos-generating periodic orbits of topological defects in confined active nematics

Fuente: arXiv
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Main Authors: Klein, Brandon, Franco, Alejandro J. Soto, Sabbir, Md Mainul Hasan, Deutsch, Matthew J., Kliegman, Ross, Selinger, Robin L. B., Mitchell, Kevin A., Beller, Daniel A.
Format: Preprint
Published: 2025
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author Klein, Brandon
Franco, Alejandro J. Soto
Sabbir, Md Mainul Hasan
Deutsch, Matthew J.
Kliegman, Ross
Selinger, Robin L. B.
Mitchell, Kevin A.
Beller, Daniel A.
author_facet Klein, Brandon
Franco, Alejandro J. Soto
Sabbir, Md Mainul Hasan
Deutsch, Matthew J.
Kliegman, Ross
Selinger, Robin L. B.
Mitchell, Kevin A.
Beller, Daniel A.
contents Active nematics in two dimensions stir themselves efficiently through internally generated chaotic flows, largely driven by motile $+1/2$ disclinations. We investigate how this tendency toward chaotic fluid stirring can, counterintuitively, produce certain ordered, periodic flows in confinement, characterized by stable periodic orbits of $+1/2$ disclinations. We computationally study two-dimensional active nematics in systems with boundary conditions requiring a prescribed number $n$ of excess $+1/2$ disclinations, using Beris-Edwards nematohydrodynamics simulations alongside an agent-based simulation approach. We find that when confinement is sufficiently strong to prevent defect pair-nucleation, but not strong enough to arrest all flow, then $n=3$ defects generically follow a "golden braid" orbit as observed recently in experiments, and we predict a "silver braid" orbit of $n=4$ defects. For these results and for greater numbers of defects, we show that the periodic or chaotic nature of the dynamics is determined by a balance between the number of defects and the number of vortices in the flow field, suggesting a new design criterion for ordered flows in active nematics.
format Preprint
id arxiv_https___arxiv_org_abs_2503_10880
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Chaos-generating periodic orbits of topological defects in confined active nematics
Klein, Brandon
Franco, Alejandro J. Soto
Sabbir, Md Mainul Hasan
Deutsch, Matthew J.
Kliegman, Ross
Selinger, Robin L. B.
Mitchell, Kevin A.
Beller, Daniel A.
Soft Condensed Matter
Active nematics in two dimensions stir themselves efficiently through internally generated chaotic flows, largely driven by motile $+1/2$ disclinations. We investigate how this tendency toward chaotic fluid stirring can, counterintuitively, produce certain ordered, periodic flows in confinement, characterized by stable periodic orbits of $+1/2$ disclinations. We computationally study two-dimensional active nematics in systems with boundary conditions requiring a prescribed number $n$ of excess $+1/2$ disclinations, using Beris-Edwards nematohydrodynamics simulations alongside an agent-based simulation approach. We find that when confinement is sufficiently strong to prevent defect pair-nucleation, but not strong enough to arrest all flow, then $n=3$ defects generically follow a "golden braid" orbit as observed recently in experiments, and we predict a "silver braid" orbit of $n=4$ defects. For these results and for greater numbers of defects, we show that the periodic or chaotic nature of the dynamics is determined by a balance between the number of defects and the number of vortices in the flow field, suggesting a new design criterion for ordered flows in active nematics.
title Chaos-generating periodic orbits of topological defects in confined active nematics
topic Soft Condensed Matter
url https://arxiv.org/abs/2503.10880