Origin of Persistent Boundary Motion in Confined Active Matter

Fuente: arXiv
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Main Authors: Baby, Elsa, Gopalakrishnan, Manoj, Vasisht, Vishwas V.
Format: Preprint
Published: 2026
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author Baby, Elsa
Gopalakrishnan, Manoj
Vasisht, Vishwas V.
author_facet Baby, Elsa
Gopalakrishnan, Manoj
Vasisht, Vishwas V.
contents Active matter systems under confinement display persistent surface motion and a strong boundary affinity. However, despite extensive studies of their positional dynamics, much less attention has been given to the corresponding orientational behavior. Here, using molecular simulations of an active Brownian particle confined within a hard circular boundary and the Fokker-Planck equation, we show that the positional distribution of the particle is directly coupled to orientational fluctuations, as characterized by the conditional orientational distribution. Confinement generates two preferred tangential orientational states connected by stochastic flipping pathways: rapid boundary-localized switching and slower bulk-mediated excursions. Further, the positional distribution exhibits a nontrivial power-law decay with distance from the boundary that is closely linked to curvature-induced bistable orientational states and the variance of the associated conditional distribution. The mean waiting time between flips exhibits power-law dependence on the confinement strength. Our results establish that the interplay between orientational fluctuations, bistability, positional accumulation, and stochastic switching governs the observed dynamics of active particles under confinement, providing a framework for understanding transport, exploration, and escape processes in confined active systems.
format Preprint
id arxiv_https___arxiv_org_abs_2605_20938
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Origin of Persistent Boundary Motion in Confined Active Matter
Baby, Elsa
Gopalakrishnan, Manoj
Vasisht, Vishwas V.
Soft Condensed Matter
Biological Physics
Active matter systems under confinement display persistent surface motion and a strong boundary affinity. However, despite extensive studies of their positional dynamics, much less attention has been given to the corresponding orientational behavior. Here, using molecular simulations of an active Brownian particle confined within a hard circular boundary and the Fokker-Planck equation, we show that the positional distribution of the particle is directly coupled to orientational fluctuations, as characterized by the conditional orientational distribution. Confinement generates two preferred tangential orientational states connected by stochastic flipping pathways: rapid boundary-localized switching and slower bulk-mediated excursions. Further, the positional distribution exhibits a nontrivial power-law decay with distance from the boundary that is closely linked to curvature-induced bistable orientational states and the variance of the associated conditional distribution. The mean waiting time between flips exhibits power-law dependence on the confinement strength. Our results establish that the interplay between orientational fluctuations, bistability, positional accumulation, and stochastic switching governs the observed dynamics of active particles under confinement, providing a framework for understanding transport, exploration, and escape processes in confined active systems.
title Origin of Persistent Boundary Motion in Confined Active Matter
topic Soft Condensed Matter
Biological Physics
url https://arxiv.org/abs/2605.20938