Understanding Dense Active Nematics from Microscopic Models

Aurelio Patelli, Ilyas Djafer-Cherif, Igor S. Aranson, Eric Bertin, and Hugues Chaté

Phys. Rev. Lett. 123, 258001 – Published 18 December 2019

Abstract

We study dry, dense active nematics at both particle and continuous levels. Specifically, extending the Boltzmann-Ginzburg-Landau approach, we derive well-behaved hydrodynamic equations from a Vicsek-style model with nematic alignment and pairwise repulsion. An extensive study of the phase diagram shows qualitative agreement between the two levels of description. We find in particular that the dynamics of topological defects strongly depends on parameters and can lead to “arch” solutions forming a globally polar, smecticlike arrangement of Néel walls. We show how these configurations are at the origin of the defect ordered states reported previously. This work offers a detailed understanding of the theoretical description of dense active nematics directly rooted in their microscopic dynamics.

Received 20 May 2019
Revised 13 September 2019

DOI:https://doi.org/10.1103/PhysRevLett.123.258001

Physics Subject Headings (PhySH)

Collective behavior Dynamical phase transitions Emergence of patterns Nonequilibrium statistical mechanics Order parameters

Statistical Physics & ThermodynamicsPolymers & Soft Matter

Authors & Affiliations

Aurelio Patelli¹, Ilyas Djafer-Cherif^1,2, Igor S. Aranson ³, Eric Bertin ⁴, and Hugues Chaté ^1,5,6

¹Service de Physique de l’Etat Condensé, CEA, CNRS, Université Paris-Saclay, CEA-Saclay, 91191 Gif-sur-Yvette, France
²School of Mathematics, University of Bristol, Bristol BS8 1TW, United Kingdom
³Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA
⁴Univ. Grenoble Alpes, CNRS, LIPhy, 38000 Grenoble, France
⁵Computational Science Research Center, Beijing 100094, China
⁶LPTMC, Sorbonne Université, CNRS, 75005 Paris, France