26 mars 2026 @ 10:45 – 11:45 – I will present a construction of the Euclidean sine–Gordon quantum field theory using probabilistic methods. The approach formulates the model through a stochastic control problem and a weak forward–backward stochastic differential equation (FBSDE). The starting point is a detailed study of the perturbation theory associated with the sine–Gordon potential across the full subcritical regime. For […]
26 mars 2026 @ 09:15 – 10:15 – Modern statistical learning problems often involve heterogeneous, high-dimensional, or distributed data, raising two complementary challenges: controlling model complexity in high dimensions, and enabling frugal inference under distributional constraints, while preserving both structure and statistical consistency. In this talk, I present contributions centered on mixture-of-experts (MoE) models, a flexible latent variable framework with well-established approximation capabilities […]
25 mars 2026 @ 16:45 – 17:45 – It is well known about the Riemann zeta function that $\zeta(2i) \in \mathbb{Q}\pi^{2i}, i\geqslant 1$, and thus all these numbers are linearly independent over $\mathbb{Q}$, since $\pi$ is transcendental. However, very little is known about the numbers $\zeta(2i+1), i\geqslant 1$. It was proved in 1978 that $\zeta(3)$ is irrational, and in 2000 that infinitely many […]
24 mars 2026 @ 09:15 – 11:45 – Dans cette exposé on considère une approximation de champ-moyen d’une étoile à bosons, qui est composé d’un grand nombre de bosons qui intéragissent entre eux et qui sont soumis aux forces gravitationnelles. L’équation qui décrit cette étoile à bosons est de type Scrhödinger non linéaire avec un potentiel de convolution. Après avoir montré l’existence d’une solution […]
24 mars 2026 @ 09:15 – 11:45 – In this talk we will consider the mean-field approximation of a boson star, which is composed of a large number of gravitating bosons interacting with each other. The resulting equation is nonlinear of Schrödinger type and with a non-local convolution potential. We will first discuss the existence of a solution to this nonlinear equation, which […]
23 mars 2026 @ 15:30 – 16:30 – In this talk, I will present the meeting of different dynamical systems: tiling billiards, the wind-tree model and the Eaton lenses. The three of them are motivated by physics. In the beginning of the 2000’s, physicists have conceived metamaterials with negative index of refraction. Tilling billiards’ trajectories consist of light rays moving in an arrangement […]
23 mars 2026 @ 14:00 – 15:00 – A couple of years ago, Ammann, Kröncke and Müller proposed a construction producing initial data sets for spacetimes with lightlike parallel spinor as studied by Baum, Leistner and Lischewski in the context of Lorentzian special holonomy. The input data for the AKM-construction essentially consists of a curve in the moduli space of Ricci-flat metrics on […]
20 mars 2026 @ 11:00 – 12:00 – We study scattering by obstacles and we consider the scattering kernel $s(t, \theta, \omega)$ which is the Fourier transform of the scattering amplitude. First, we prove the Poisson relation which says that the singularities of scattering kernel with respect to t are included in the set of sojourn times of generalised rays incoming with direction […]
19 mars 2026 @ 19:00 – 20:30 – Le hasard fait partie intégrante de notre quotidien, mais il nous joue souvent des tours. À travers une série de paradoxes probabilistes, certains issus de situations bien réelles et d’autres volontairement imaginés, cette conférence invite à remettre en question nos réflexes spontanés face à l’aléatoire. Pourquoi notre intuition nous induit-elle si souvent en erreur ? […]
19 mars 2026 @ 14:15 – 15:15 – Let $X$ be a compact hyperbolic surface with finite order singularities and $X_1$ its unit tangent bundle. We consider the twisted Selberg zeta function $Z(s; \rho)$ associated with a representation $\rho: \pi_1(X_1) → GL(V_\rho)$. In this talk, we will present recent results concerning a relation between the twisted Selberg zeta function $Z(s; \rho)$ and the […]