Defect Ordering in Confined Chiral Active Liquid Crystals

Chiral structures and dynamics are common in active systems, from biomolecules to microswimmers. However, the role of chiral activity in dense, confined active matter is underexplored. Using a hydrodynamic model, we investigate +1/2 defect dynamics in confined chiral active nematics (CAN) and between CAN droplets. For a CAN confined to a disk, tuning linear and chiral activity reveals diverse defect dynamics, including spirograph, steady rotation, circular motion, stable lattice, and active turbulence modes. Experimental results using a rotating magnetic field confirm our predictions of defect chirality and provide insights for designing chiral active liquid crystals. For interacting CAN droplets, hydrodynamic coupling drives distance-dependent transitions between synchronization modes, including in-phase and anti-phase ferromagnetic state and anti-ferromagnetic state in achiral drops. For multiple CAN droplets in triangular and square geometry, we uncover spin-glass-like patterns of defect configurations driven by hydrodynamics, geometric frustration, and chiral activity. As such, our findings offer new insights into temporal order in chiral active matter, and provide new ways to spatiotemporally control active defects.