Emergent Dynamics in Classical Many-Body Systems
Systems driven far from equilibrium exhibit a diverse range of collective phenomena. Recently, studies of "active matter" have been of interest where individual particles input energy into the system and control the dynamics. Alternatively, many-body systems can be driven by external, active fields which couples to the constituents in some nonlinear way. Although no universal framework exists for describing nonequilibrium systems, in many cases a steady state is reached where some aspects of equilibrium theories can be applied. However, nonequilibrium systems often never reach a steady state, and constantly switch behavior. In this talk I will present experimental evidence that bistable elements are not required for the global bistability of a system. In our experiments, we observe temporal switching between a crystalline, condensed state and a gaslike, excited state in a spatially-extended, quasi-two-dimensional system of charged microparticles. Accompanying numerical simulations show that conservative forces, damping, and stochastic noise are sufficient to prevent steady-state equilibrium, leading to switching between the two states over a range of emergent time scales, from seconds to hours. I will also discuss how this system can serve as a simple model for intermittent dynamics and energy cascades in other complex systems.