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Thursday, February 21, 2019 - 11:15 to 12:30 Auditorium
Understanding the physics of irreversible processes that occur in far from equilibrium systems is of both fundamental and practical importance. However, these problems pose unique challenges as dynamic irreversible processes are far from steady and probing them requires keeping up with them as the system navigates across a complex landscape. Such challenges, as they manifest in turbulence, were beautifully portrayed by Richardson: “Big whirls have little whirls that feed on their velocity, and little whirls have lesser whirls and so on to viscosity” Lewis Fry Richardson (1922) This statement captures the essence of the turbulent cascade—the conveyance of kinetic energy across scales that underlies the universal dynamics of turbulent flows. Indeed, such conveyance of important physical quantities (energy, stress, frustration and even information) down and up a vast range of scales underlie the dynamics of many systems. For example, these same concepts hold for multi-contact frictional interfaces that form and break, for correlated defect structures that determine the strength of metals, and even in intricate networks of creases that form when a thin sheet of paper is crumpled or a soda can is smashed. We have developed experimental techniques that enable one to capture these dynamic events across multiple time and length scales. In this talk, I will describe our observations on several irreversible systems using these new tools that shed new light on their far from equilibrium behavior.