Séminaire Analyse-Probabilités

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Intervenant : VANNEUVILLE Hugo (Institut Fourier (Université Grenoble Alpes))
Titre :
Noise sensitivity for percolation

Le : 09/12/2025 de : 10:30 à : 11:30
Let us consider the hexagonal lattice, let us randomly color each hexagon independently black or white with probability 1/2, and look at percolation events (for example, the event that there is a black path from left to right in a large square). Benjamini, Kalai, and Schramm proved that percolation properties are noise sensitive, which means that if we introduce a ‘noise’ -- even very small -- to the colors of the hexagons, then the percolation events after and before the noise are quasi-independent of each other. In this talk, we would like to propose a ‘robust’ approach -- i.e., one that extends to more general models, for example where the colors are not independent of each other -- to noise sensitivity. Unlike previous approaches, we do not rely on spectral tools but on differential inequalities satisfied by the probabilities of so-called ‘4-arm’ events, which are at the heart of Kesten's work in the 1980s and which we will define. Joint work with Vincent Tassion.
Salle : A711

Séminaire Analyse-Probabilités

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Intervenant : SALORT Delphine (LJLL, Sorbonne Université)
Titre :
Asymptotic dynamic of neural models with partial diffusion

Le : 16/12/2025 de : 10:30 à : 11:30
In many biological contexts, one observes Brownian motions that are restricted to certain variables or random movements that differ from classical Brownian motion. Among these mod- els are those involving large populations of interacting neurons. In such models, the variability of neuronal ion channels, which are also subject to random fluctuations, is modeled by diffusion in the conductance variable, while the membrane potential variable remains non-diffusive. Other models focus exclusively on the membrane potential (without conductance) and include an adaptation variable that responds to stimuli received by the neurons. In this case, diffusion is applied to the membrane potential, while the adaptation variable remains non-diffusive. All these phenomena can lead to changes in propagation speed and, in some cases, a significant loss of regularity properties. In this talk, we will explain, using two toy models from neuroscience, how to study the asymptotic properties of these equations and deduce the exponential convergence of the solution toward the stationary state in L^1.
Salle : A711

Séminaire Analyse-Probabilités

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Intervenant : GRASSELLI Viviana (IECL - Metz)
Titre :


Le : 27/01/2026 de : 10:30 à : 11:30

Salle : A711

Séminaire Analyse-Probabilités

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Intervenant : VAN DEN BOSCH Hanne (Universidad de Chile)
Titre :
TBA

Le : 17/02/2026 de : 09:00 à : 09:00

Salle : A711

Séminaire Analyse-Probabilités

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Intervenant : SUN Changzhen (CNRS & Laboratoire de Mathématiques de Besançon)
Titre :


Le : 14/04/2026 de : 10:30 à : 11:30

Salle : A711

Séminaire Analyse-Probabilités

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Intervenant : AYI Nathalie (LJLL)
Titre :
TBA

Le : 19/05/2026 de : 10:30 à : 11:30
TBA
Salle : A711