| Les deux révisions précédentes Révision précédente Prochaine révision | Révision précédente Prochaine révisionLes deux révisions suivantes |
| mega:seminaire [2020/05/14 20:56] – [Calendrier 2019-2020] Guillaume BARRAQUAND | mega:seminaire [2020/05/29 16:04] – [Prochaine séance] Guillaume BARRAQUAND |
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| * **Calendrier.** https://calendar.google.com/calendar/ical/qn5qq7dlmp38sc624s4png8umc%40group.calendar.google.com/public/basic.ics | * **Calendrier.** https://calendar.google.com/calendar/ical/qn5qq7dlmp38sc624s4png8umc%40group.calendar.google.com/public/basic.ics |
| ===== Prochaine séance ===== | ===== Prochaine séance ===== |
| Vendredi **15 mai**, en vidéoconférence via BigBlueButton, accessible par ce [[https://webconf.math.cnrs.fr/b/gui-cw9-efz|lien]], | Vendredi **5 juin**, en vidéoconférence via BigBlueButton, accessible par ce [[https://webconf.math.cnrs.fr/b/gui-cw9-efz|lien]], |
| * 14h00-15h00: **[[https://irma.math.unistra.fr/~vogel/|Martin Vogel]]**// Spectra of Toeplitz matrices subject to small random noise.//\\ | * 14h00-15h00: **[[http://google.com/search?q=Joseph+Najnudel|Joseph Najnudel]]** ////\\ |
| Abstract: The spectra of nonselfadjoint linear operators can be very unstable and sensitive to small perturbations. This phenomenon is usually referred to as "pseudospectral effect". To explore this spectral instability we study the spectra of small random perturbations of non-selfadjoint operators in the case of Toeplitz matrices and in the case of the Toeplitz quantization of complex-valued functions on the torus. We will discuss recent results by Sjöstrand, Vogel and by Basak, Paquette and Zeitouni, describing the distribution of the eigenvalues in various regimes and settings. | Abstract: |
| * 15h30-16h30: **[[http://www.statslab.cam.ac.uk/~rb812/|Roland Bauerschmidt]]**// Random spanning forests and hyperbolic symmetry.//\\ | |
| Abstract: We study (unrooted) random forests on a graph where the probability of a forest is multiplicatively weighted by a parameter $\beta>0$ per edge. This model is the $q\to 0$ limit of the random cluster model with $p=q\beta$. It is also known under different names such as the arboreal gas or the uniform forest model. In this talk, I will discuss the tantalizing conjectural behaviour of the model, and then present our result that there is no percolation in dimension two. This result relies on a surprising hyperbolic symmetry and methods previously developed for linearly reinforced walks. (This is joint work with Nick Crawford, Tyler Helmuth, and Andrew Swan.) | * 15h30-16h30: **[[https://sites.google.com/view/theoassiotis/publications|Theodoros Assiotis]]** // Joint moments of the characteristic polynomial of a random unitary matrix.//\\ |
| | Abstract: I will speak about the joint moments of the characteristic polynomial of a random unitary matrix and its derivative. In joint work with Jon Keating and Jon Warren, by developing a connection with the Hua-Pickrell measures and using a probabilistic approach, we establish these asymptotics for general real values of the exponents which proves a conjecture from the thesis of Hughes from 2001. |
| ===== Calendrier 2019-2020 ===== | ===== Calendrier 2019-2020 ===== |
| * **Organisateurs 2019-2020.** | * **Organisateurs 2019-2020.** |