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Widely Applied Mathematics Seminars

On the nature of the glass transition

Matthieu Wyart, Professor of Physics, EPFL

Thursday, Feb 2, 2023

Under cooling, a supercooled liquid undergoes a glass transition and stops flowing. Physicists do not agree on the microscopic reasons that make a glass solid. Some view this phenomenon as being collective in nature: it may be a signature of a thermodynamic phase transition, or  being caused by kinetic constraints (where particles seek to solve a sort of Chinese puzzle). Others view it as simply reflecting elementary barriers for rearrangements, controlled by the elasticity of the material. Here I will focus on  polydisperse numerical glasses, which are receiving a considerable attention, because they can be equilibrated as efficiently as experimental molecular liquids. I will  Introduce a novel algorithm to systematically extract elementary rearrangements in a broad energy range. It allows to make, for the first time, a quantitative prediction on the relaxation time, assuming that relaxation is not collective in nature. The comparison with observation is very good. I will explain why, in such a scenario, dynamical correlations emerge even if they have little effects on the dynamics.  I will discuss the nature of elementary rearrangements under cooling, and how these aspects relate to mean field description of glasses.


Speaker Bio

Matthieu Wyart studied physics, mathematics and economics at the Ecole Polytechnique in Paris where he obtained in 2001 his degree in physics with Honors  and, the following year, the Diploma of Advanced Studies in Theoretical Physics, with highest Honors at the Ecole Normale Supérieure, Paris.

In 2006 he obtained a doctoral degree in Theoretical Physics and Finance at the SPEC, CEA Saclay, Paris with a thesis on electronic markets. He then moved to the United States, to Harvard, Janelia farm, and Princeton before joining in 2010 New York University as Assistant Professor, where he was promoted Associate professor in 2014.

In July 2015, he was appointed Associate Professor of Theoretical Physics in the School of Basic Sciences at EPFL.


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