Centre de Physique Théorique


Vendredi 21 février 2020

14h00 – 15h00, online-for link write to Annalisa Panati

Semiclassical limit from the Hartree equation to the Vlasov-Poisson system

Chiara Saffirio, Université de Basel, Suisse

The derivation of the Vlasov-Poisson equation, that describes the evolution of a systems of N interacting non-collisional particles at macroscopic scale, is a classical problem in mathematical physics. In this talk we will review this topic in the quantum setting, by using the Hartree equation as a bridge between the N-body Schrödinger equation and the Vlasov-Poisson system. We will show that a solution of the Hartree equation converges strongly towards a solution of the Vlasov-Poisson equation in the semiclassical limit.
The results hold for singular interactions (included the Coulomb and gravitational potentials) and exhibit explicit bounds on the convergence rate.

14h00 – 15h00, Amphi 5 du CPT

General Relativity from Scattering Amplitudes

Poul Damgaard (Niels Bohr Institute)

A remarkable connection between the loop expansion of quantized gravity and classical general relativity allows for the computation of two-body dynamics in general relativity using a number of new amplitude tools developed in recent years. The resulting expansion is known as Post-Minkowskian (in contradistinction to Post-Newtonian) and the new method promises to overturn all previously used techniques for analytical calculations of gravitational wave signals of two merging black holes. I will outline the program and illustrate with examples of the calculation of classical gravitational scattering angles.