Dynamic Instabilities and Pattern Formation in Chemotactic Active Matter

Fuente: arXiv
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Hauptverfasser: Zhao, Hongbo, Yu, Qiwei, Košmrlj, Andrej, Datta, Sujit S.
Format: Preprint
Veröffentlicht: 2026
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author Zhao, Hongbo
Yu, Qiwei
Košmrlj, Andrej
Datta, Sujit S.
author_facet Zhao, Hongbo
Yu, Qiwei
Košmrlj, Andrej
Datta, Sujit S.
contents Collectives of actively-moving particles can spontaneously segregate into dilute and dense phases through a process known as motility-induced phase separation (MIPS). This captivating phenomenon is well-studied for randomly-moving particles with no directional bias. However, many active systems perform collective chemotaxis -- directed motion along a chemical gradient collectively generated by the particles themselves through consumption or production. Here, we use linear stability analysis, amplitude equations, and numerical simulations to study how MIPS is influenced by collective chemotaxis. We find that chemotaxis can either arrest or entirely suppress MIPS, or give rise to novel dynamic instabilities such as traveling waves and spirals. We predict the stability region of the stationary and oscillatory patterns and identify four types of bifurcation that can arise: pitchfork, saddle-node, infinite period, and supercritical Hopf. We also derive analytical expressions for the amplitude of the pattern and traveling wave velocity, yielding excellent quantitative agreement with simulations. Furthermore, we generalize our model to study particles that either consume or produce chemoattractant or chemorepellent, as well as mixtures of particles with different chemotactic behaviors. By establishing quantitative principles describing the competition between MIPS and chemotaxis, our study helps deepen understanding of the rich physics underlying chemically-responsive active matter systems.
format Preprint
id arxiv_https___arxiv_org_abs_2603_02595
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Dynamic Instabilities and Pattern Formation in Chemotactic Active Matter
Zhao, Hongbo
Yu, Qiwei
Košmrlj, Andrej
Datta, Sujit S.
Soft Condensed Matter
Statistical Mechanics
Pattern Formation and Solitons
Biological Physics
Collectives of actively-moving particles can spontaneously segregate into dilute and dense phases through a process known as motility-induced phase separation (MIPS). This captivating phenomenon is well-studied for randomly-moving particles with no directional bias. However, many active systems perform collective chemotaxis -- directed motion along a chemical gradient collectively generated by the particles themselves through consumption or production. Here, we use linear stability analysis, amplitude equations, and numerical simulations to study how MIPS is influenced by collective chemotaxis. We find that chemotaxis can either arrest or entirely suppress MIPS, or give rise to novel dynamic instabilities such as traveling waves and spirals. We predict the stability region of the stationary and oscillatory patterns and identify four types of bifurcation that can arise: pitchfork, saddle-node, infinite period, and supercritical Hopf. We also derive analytical expressions for the amplitude of the pattern and traveling wave velocity, yielding excellent quantitative agreement with simulations. Furthermore, we generalize our model to study particles that either consume or produce chemoattractant or chemorepellent, as well as mixtures of particles with different chemotactic behaviors. By establishing quantitative principles describing the competition between MIPS and chemotaxis, our study helps deepen understanding of the rich physics underlying chemically-responsive active matter systems.
title Dynamic Instabilities and Pattern Formation in Chemotactic Active Matter
topic Soft Condensed Matter
Statistical Mechanics
Pattern Formation and Solitons
Biological Physics
url https://arxiv.org/abs/2603.02595