le 31 janvier 2024
Publié le 26 octobre 2023 Mis à jour le 14 novembre 2023

Guest Lecture : Antonio Politi

Breathers and transport in statistical systems with two conservation laws

Antonio Politi est professeur émérite de physique à l'Université d'Aberdeen

Statistical systems characterized by two conservation laws may exhibit peculiar properties.
As an example, the resulting coupled traNsport may induce non monotonous temperature profiles.
Furthermore, a region of absolute negative temperatures may arise, characterized by the spontaneous emergence of breather-like solutions accompanied by a progressive coarsening.
Last but not least, negative temperatures may spontaneously emerge in the evolution of "standard" nonequilibrium stationary states, while the heat baths operate at
positive temperatures.

I'll mostly focus on two systems: the deterministic Discrete NonLinear Schroedinger equation (DNLS) and a stochastic model of non-interacting particles.
In the second setup, theoretical considerations can be carried out and numerical simulations are far more reliable. In particular, general features of the stationary regimes can be determined with the help of linear transport theory.  As a result, one can understand the reason why stationary nonequilibrium states may generically enter the negative temperature region.

In the DNLS< The expected scenario is rather similar, but with an important difference: the presence of an adiabatic invariant makes the entire dynamics much slower, in the presence of tall breathers.

Date : 5 décembre 2023 de 14h00 à 15h30

La guest lecture hybride est organisée en présence dans la salle de réunion H008 de la MIR à Neuville-sur-Oise et à distance sur Zoom.

Pour participer à la guest lecture à distance, connectez-vous sur Zoom : https://cyu-fr.zoom.us/j/91398173209

ID réunion : 913 9817 3209

La vidéo sera publiée sur la chaîne YouTube de CYAS