The equilibrium and nonequilibrium dynamics of a soft medium, such as superconducting vortices, colloids, granular materials, or biological systems, can be readily accessed by driving a single particle through the system. The resulting local probe couples directly to the length and energy scales of heterogeneities in the material, and can be used to explore not only the equilibrium response of the media on long time scales, but can also access the strongly nonequilibrium responses that occur on time scales faster than the relaxation time. This makes the local probe ideal for studying intermittency and glassiness. I will describe the novel features uncovered by a local probe at a melting transition in a soft lattice and at a depinning transition for a system with quenched disorder. I will also show that a diverging length scale at the jamming transition in granular media, which is easily accessed with a local probe, could imply that the glass transition is a true phase transition.
Coffee and cookies before the presentation at 3:15 pm, and refreshments after the presentation will both be served in Room 128.