Braiding active nematics

Active materials are a new paradigm in soft matter physics, composed of individual agents with an internal power source. Examples from nature include sheets of cells and swarms of bacteria. Examples from the lab include biomimetic and synthetic active materials such as dense phases of biopolymers driven by molecular motors. Since the agents' internal energy drives them out of equilibrium, traditional thermodynamics techniques are no longer applicable and new perspectives are required. Tools from dynamical systems have proven to be one such fruitful approach. Active materials typically exhibit emergent collective behavior, including local order with topological defects where that order breaks down. Many active systems exhibit beautiful chaotic advection patterns to which the tools of nonlinear dynamics and chaos are readily applied. Techniques from machine learning have also been used to learn the dynamics of such systems. This talk will provide a snapshot of various dynamical systems techniques being used to elucidate the rich behavior of active materials.