Active Elastic Network

Active elastic networks model the cytoskeleton: actin filaments (edges) cross-linked at nodes, driven by myosin motors that generate contractile stress. The activity parameter α sets motor force magnitude. Above a critical activity, the network undergoes spontaneous symmetry breaking — stress fibers (thick, aligned bundles) emerge. Color encodes local tension (red = high tension, blue = compression). Nodes move overdampedly to minimize elastic + active energy.