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Home page > Séminaires > Séminaires 2022 > MSC Seminar. November 21th 2022 at 11:00, Matthieu Wyart (EPFL, Lausanne) :" On the nature of the glass transition.".

MSC Seminar. November 21th 2022 at 11:00, Matthieu Wyart (EPFL, Lausanne) :" On the nature of the glass transition."

Sauf mention contraire, les séminaires et les soutenances se déroulent à 11h30 en salle 454A du bâtiment Condorcet.

There will be a live diffusion with Zoom :

Exceptionnal Schedule Monday November 21th, 11h00 in room 454 A.

Please contact Michael Berhanu to attend the visio-seminar.

On the nature of the glass transition

Matthieu Wyart

Physics of Complex Systems Laboratory

Professor of Theoretical Physics at Ecole Polytechnique Fédérale de Lausanne, Switzerland

Abstract : 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 (i) design new algorithms that can continuously speed up or slow down the normal physical dynamics, ruling out the role of a thermodynamic phase transition [1]. (ii) 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 excellent [2]. (iii) I will explain why, in such a scenario, dynamical correlations emerge even if they have little effects on the dynamics [3]. (iv) I will discuss the nature of elementary rearrangements under cooling, and how these aspects relate to mean field description of glasses.

[1] ongoing work with Cristina Gavazzoni and Carolina Brito [2] ongoing work with Wencheng Ji and Massimo Pica Ciamarra [3] ongoing work with Giulio Biroli, Misaki Ozawa, Marko Popovic and Ali Tahaei [4] joint work with Wencheng Ji, Tom WJ de Geus and Elisabeth Agoritsas

Illustration for the systematic search algorithm of excitations in glasses, where low-energy excitations are stabilised once detected to allow for the discovery of higher energy ones.

Contact : Équipe séminaires / Seminar team - Published on / Publié le 4 novembre 2022

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