Abstract
Active nematics are microscopically driven liquid crystals that exhibit
dynamical steady states characterized by the creation and annihilation of
topological defects. Motivated by experimental realizations of such systems
made of biopolymer filaments and motor proteins, we describe a large-scale
simulation study of a particle-based computational model that explicitly
incorporates the semiflexibility of the biopolymers. We find that energy
injected into the system at the particle scale preferentially excites bend
deformations, renormalizing the filament bend modulus to smaller values. The
emergent characteristics of the active nematic depend on activity and
flexibility only through this activity-renormalized bend modulus, demonstrating
that material parameters such as the Frank `constants' must explicitly depend
on activity in a continuum hydrodynamic description of an active nematic.
Further, we present a systematic way to estimate these material parameters from
observations of deformation fields and defect shapes in experimental or
simulation data.