Contractile Active Matter — Actomyosin Cytoskeleton

Self-propelled polar particles with alignment; ±½ defect dynamics in active nematic

Active polar fluid model
Vicsek-like alignment + activity
Contractile: ζ < 0 → asters
Extensile: ζ > 0 → extensile jets
±½ defects (nematic symmetry)
Defects self-propel in active nematics