Guest Lecture: Antonio Politi

Breathers and transport in statistical systems with two conservation laws

Antonio Politi is Emeritus Professor of Physics at the University of 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: 13 February 2024  from 14:00 to 15:30

The hybrid guest lecture is organised in person at the H008 Meeting Room of MIR in Neuville-sur-Oise and remotely on Zoom.

To attend the remote guest lecture, please connect to Zoom: https://cyu-fr.zoom.us/j/94353574410

Meeting ID: 943 5357 4410

The video will be online on the CY AS YouTube channel