Mesoscopic Simulations of Active-Nematics

TL;DR

This paper introduces a mesoscopic simulation algorithm for active nematics that captures turbulence and bridges microscopic and continuum models, enabling studies of complex active-passive systems.

Contribution

The authors develop a novel active nematic MPCD algorithm incorporating dipolar activity, expanding coarse-grained simulation capabilities for active matter.

Findings

Reproduces key features of active nematic turbulence

Bridges microscopic and continuum descriptions

Enables simulations of active-passive composite systems

Abstract

Coarse-grained, mesoscale simulations are invaluable for studying soft condensed matter because of their ability to model systems in which a background solvent plays a significant role but is not the primary interest. Such methods generally model passive solvents; however, far-from-equilibrium systems may also be composed of complex solutes suspended in an active fluid. Yet, few coarse-grained simulation methods exist to model an active medium. We introduce an algorithm to simulate active nematics, which builds on multi-particle collision dynamics (MPCD) for passive fluctuating nematohydrodynamics by introducing dipolar activity in the local collision operator. Active-nematic MPCD (AN-MPCD) simulations exhibit the key characteristics of active nematic turbulence but, as a particle-based algorithm, also reproduce crucial attributes of active particle models. Thus, mesoscopic AN-MPCD is an approach that bridges microscopic and continuum descriptions, allowing novel simulations of composite active-passive systems.