Active Topology

Topology plays a key role in condensed matter physics, underlying much of our understanding of equilibrium matter in terms of defects in ordered media and topologically protected states. In active systems – collections of entities that consume energy to generate their own motion and forces – topological phenomena can take on new and surprising roles. I will describe some of these behaviors focusing on liquid-crystalline active matter in two dimensions, specifically active nematic liquid crystals, where defects become motile particles, drive spatio-temporally chaotic flows, and can themselves organize in emergent ordered states.