Muhittin Mungan

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Understanding the response of a disordered solid to an externally imposed forcing or deformation is important in order to characterize the transitions between rigid and flowing states in a wide variety of soft matter systems, such as the yielding transition of an amorphous solid under shear. Such complex phenomena are already present in the "AQS" regime where thermal effects are negligible, the response to forcing is quasi-static, and the dynamics proceeds via triggering of mechanical instabilities. A key insight underlying my recent research has been the observation that the AQS conditions permit a rigorous representation of the driven dynamics in term of a directed state-transition graph. This AQS graph represents the response of the system to any deformation protocol, providing thereby a bird's-eye (or map-like) view of all the possible dynamics, which in turn is encoded in the topology of the AQS graph. At the same time, the AQS graph is a discrete random structure that lends itself to a mathematical treatment. In this talk I will describe the energy landscape of a sheared amorphous solid via AQS transition graphs, highlighting key features, such as hysteresis, and showing how various topological properties of this graph can be captured in terms of stochastic models.

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University of Bonn
Online via zoom
Contact: Joachim Krug