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  • Open Access

Coarse-graining dense, deformable active particles

Mehrana R. Nejad1,2,* and Julia M. Yeomans3

  • 1Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
  • 2School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
  • 3The Rudolf Peierls Centre for Theoretical Physics, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom

  • *Contact author: mehrana@g.harvard.edu
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Phys. Rev. Research 7, 043070 – Published 17 October, 2025

DOI: https://doi.org/10.1103/phtt-7db6

Abstract

We coarse-grain a model of closely packed ellipses that can vary their aspect ratio to derive continuum equations for materials comprising confluent deformable particles such as epithelial cell layers. We show that contractile nearest-neighbor interactions between ellipses can lead to their elongation and nematic ordering. Adding flows resulting from active hydrodynamic stresses produced by the particles also affects the aspect ratio and can result in active turbulence. Our results, which agree well with multiphase field simulations of deformable isotropic cells, provide a bridge between models that explicitly resolve cells and continuum theories of active matter.

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Outline

Information

Phys. Rev. Research 7, 043070– Published 17 October, 2025
  • Received 20 October 2024
  • Accepted 23 September 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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