Séminaire BBT

 

Organisé à tour de rôle par des membres du BCAM, de l’IMB et de l’IMT, le séminaire Bilbao-Bordeaux-Toulouse (BBT) est centré autour des thématiques du GdR Analyse des EDP, avec une ouverture vers l’analyse numérique et les probabilités. Il a lieu un mardi par mois, à 11h et est diffusé en visio-conférence avec, autant que possible, l’orateur présent sur l’un des trois sites.

1ère séance : 6 Avril 2021

Pierre Degond (IMT) – Topological states in collective dynamics

Résumé : States of matter are characterized by different types of order. Recently, a new notion of order, popularized by the 2016 physics nobel prizes, has emerged : that of topological order. It refers to the global rigidity of the system arising from topological constraints. Recently, topological states has been shown to exist in collective dynamics, which describes systems of self-propelled particles. In this work, we consider a system of self-propelled solid bodies interacting through local full body alignment proposed in a joint work with A. Frouvelle, S. Merino-Aceituno and A. Trescases. In the large-scale limit, this system can be described by hydrodynamic equations with topologically non-trivial explicit solutions. At the particle level, these solutions undergo topological phase transitions towards trivial flocking states. Numerically we show that these transitions require the system to pass through a phase of disorder. To our knowledge, it is the first time that a hydrodynamic model guides the design of topologically non-trivial states and allows for their quantitative analysis and understanding. On the way, we will raise interesting mathematical questions underpinning the analysis of collective dynamics systems.
Joint work with Antoine Diez and Mingye Na (Imperial College London)

Site organisateur : Toulouse (J.M. Bouclet, R. Duboscq, M. Maris, A. Trescases)

Video of the talk : https://www.youtube.com/watch?v=EIBfmIJbnFo

2ème séance : 11 Mai 2021

3ème séance : 15 Juin 2021