Speaker
Description
Topological defects govern the large-scale dynamics of active nematic systems, yet their behavior depends sensitively on the underlying filament kinetics. In particular, treadmilling and stochastic growth–shrinkage (catastrophe) represent distinct microscopic mechanisms that generate active stresses, raising the question of how these dynamics influence defect evolution and system ordering.
Here, we compare active nematic systems composed of treadmilling filaments and filaments undergoing catastrophic dynamics using numerical simulations. We quantify defect coarsening, global nematic order, and filament statistics across a range of conditions.
We observe that defect density decays in time following a scaling law, with comparable coarsening behavior between the two systems within current estimates. Treadmilling systems exhibit higher nematic order and shorter, more uniform filament lengths, while catastrophic dynamics lead to longer filaments and increased disorder. Despite these differences, we identify an effective length scale that collapses the ordering behavior of both systems onto a universal curve.
We further quantify defect–defect interactions through analysis of defect trajectories and pair statistics, linking microscopic filament kinetics to emergent collective dynamics. These results provide a unified framework for understanding how filament turnover mechanisms control topological defect behavior in active materials and biological systems.