NONTECHNICAL SUMMARY This award supports theoretical and computational research, and education on active matter. Active matter refers to ``materials’’ formed not of atoms or molecules, but of self-powered entities, such as birds, living cells, or man-made microswimmers, that take energy from the environment to self-organize and produce coordinated motion. An example is a bacterial suspension. Each bacterium is an active particle that swims by consuming nutrients. A dense swarm of bacteria behaves collectively as a living fluid that can flow with no externally applied forces or ``freeze” into a solid-like biofilm – a highly resistant bacterial aggregate like the tartar that forms between our teeth. This type of emergent behavior, where a collection of many interacting entities exhibits large-scale spatial or temporal organization in a state with novel macroscopic properties, is familiar in inanimate or passive matter (e.g., the transition from water to ice as one lowers the temperature), but acquires a new unexplored richness in active systems that are tuned not by an external “knob”, like temperature, but by energy generated internally by each individual. Previous active matter research has focused largely on the behavior of active fluids that exhibit self-sustained, often chaotic, flows. The first part of the work carried out in this project focuses on the largely unexplored behavior of active solids where energy input at the local scale can drive global oscillations