Spontaneous Flows and Quantum Analogies in Heterogeneous Active Nematic Films

Fuente: arXiv
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Main Authors: Houston, Alexander J. H., Mottram, Nigel J.
Format: Preprint
Published: 2024
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author Houston, Alexander J. H.
Mottram, Nigel J.
author_facet Houston, Alexander J. H.
Mottram, Nigel J.
contents Incorporating the inherent heterogeneity of living systems into models of active nematics is essential to provide a more realistic description of biological processes such as bacterial growth, cell dynamics and tissue development. Spontaneous flow of a confined active nematic is a fundamental feature of these systems, in which the role of heterogeneity has not yet been considered. We therefore determine the form of spontaneous flow transition for an active nematic film with heterogeneous activity, identifying a correspondence between the unstable director modes and solutions to Schrödinger's equation. We consider both activity gradients and steps between regions of distinct activity, finding that such variations can change the signature properties of the flow. The threshold activity required for the transition can be raised or lowered, the fluid flux can be reduced or reversed and interfaces in activity induce shear flows. In a biological context fluid flux influences the spread of nutrients while shear flows affect the behaviour of rheotactic microswimmers and can cause the deformation of biofilms. All the effects we identify are found to be strongly dependent on not simply the types of activity present in the film but also on how they are distributed.
format Preprint
id arxiv_https___arxiv_org_abs_2411_03306
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Spontaneous Flows and Quantum Analogies in Heterogeneous Active Nematic Films
Houston, Alexander J. H.
Mottram, Nigel J.
Soft Condensed Matter
Incorporating the inherent heterogeneity of living systems into models of active nematics is essential to provide a more realistic description of biological processes such as bacterial growth, cell dynamics and tissue development. Spontaneous flow of a confined active nematic is a fundamental feature of these systems, in which the role of heterogeneity has not yet been considered. We therefore determine the form of spontaneous flow transition for an active nematic film with heterogeneous activity, identifying a correspondence between the unstable director modes and solutions to Schrödinger's equation. We consider both activity gradients and steps between regions of distinct activity, finding that such variations can change the signature properties of the flow. The threshold activity required for the transition can be raised or lowered, the fluid flux can be reduced or reversed and interfaces in activity induce shear flows. In a biological context fluid flux influences the spread of nutrients while shear flows affect the behaviour of rheotactic microswimmers and can cause the deformation of biofilms. All the effects we identify are found to be strongly dependent on not simply the types of activity present in the film but also on how they are distributed.
title Spontaneous Flows and Quantum Analogies in Heterogeneous Active Nematic Films
topic Soft Condensed Matter
url https://arxiv.org/abs/2411.03306