Dinakar Ramakrishnan (Caltech)
Title T.B.A.
10:00 • EPF Lausanne
Matt Koster (Toronto)
The topology of moduli spaces of flat connections. abstract
Abstract:
We start by introducing the moduli space of flat connections on a principal PSL(2;R)-bundle P over a closed orientable surface of genus g>1. We will then describe some results on the topology of the moduli space, as well as some conjectures.
10:15 • Université de Genève, Section de mathématiques, 7-9 rue du Conseil-Général, Room 1-07
Nicola Cavalucchi (EPFL)
Convergence of CAT(0) groups and spaces abstract
Abstract:
We describe the possible limits of uniformly cocompact CAT(0)-group actions with a particular interest on the collapsing case. As an application we show a corollary on the finiteness of such groups. If there is enough time we will see how totally disconnected, unimodular groups enter naturally in the discussion.
10:20 • Université de Fribourg, 1.309 PER07
Ce Ji (Beijing Univ. and ETH Zürich)
Toward a generalization of the Witten conjecture from spectral curve abstract
Abstract:
Over decades of development of the Witten conjecture, Many enumerative geometries are related to integrable hierarchies. Simultaneously, such theories can also be reconstructed from topological recursion, an algorithm producing multi-differential forms from the underlying spectral curve. In this talk, we propose a generalization of the Witten conjecture from spectral curve, which produce descendent potential functions for corresponding enumerative geometry related to certain reductions of (multi-component) KP hierarchy. Proof for genus zero spectral curve with one boundary will be sketched, which can be applied to deduce the rKdV integrability of deformed negative r-spin theory, conjectured by Chidambaram--Garcia-Falide--Giacchetto.
13:30 • ETH Zentrum, Rämistrasse 101, Zürich, Building HG, Room G 43
Stefanie Zbinden (Heriot-Watt)
From strong contraction to hyperbolicity abstract
Abstract:
For almost 10 years, it has been known that if a group contains a strongly contracting element, then it is acylindrically hyperbolic. Moreover, one can use the Projection Complex of Bestvina, Bromberg and Fujiwara to construct a hyperbolic space where said element acts WPD. For a long time, the following question remained unanswered: if Morse is equivalent to strongly contracting, does there exist a space where all generalized loxodromics act WPD? In this talk, I will present a construction of a hyperbolic space, that answers this question positively.
15:45 • ETH Zentrum, Rämistrasse 101, Zürich, Building HG, Room G 43
Prof. Dr. Gianluca Crippa (Departement Mathmatik und Informatik, Universität Basel)
Anomalous dissipation in fluid dynamics abstract
Abstract:
Kolmogorov\'s K41 theory of fully developed turbulence advances quantitative predictions on anomalous dissipation in incompressible fluids: although smooth solutions of the Euler equations conserve the energy, in a turbulent regime information is transferred to small scales and dissipation can happen even without the effect of viscosity, and it is rather due to the limited regularity of the solutions. In rigorous mathematical terms, however, very little is known. In a recent work in collaboration with M.~Colombo and M.~Sorella we consider the case of passive-scalar advection, where anomalous dissipation is predicted by the Obukhov-Corrsin theory of scalar turbulence. In my talk, I will present the general context and illustrate the main ideas behind our construction of a velocity field and a passive scalar exhibiting anomalous dissipation in the supercritical Obukhov-Corrsin regularity regime. I will also describe how the same techniques provide an example of lack of selection for passive-scalar advection under vanishing diffusivity, and an example of anomalous dissipation for the forced Euler equations in the supercritical Onsager regularity regime (this last result has been obtained in collaboration with E.~Bru\\`e, M.~Colombo, C.~De Lellis, and M.~Sorella).
16:30 • ETH Zentrum, Rämistrasse 101, Zürich, Building HG, Room E 1.2
Prof. Dr. Nathanael Berestycki (University of Vienna)
Weyl law in Liouville quantum gravity abstract
Abstract:
Can you hear the shape of Liouville quantum gravity (LQG)?We obtain a Weyl law for the eigenvalues of Liouville Brownian motion: the n-th eigenvalue grows linearly with n, with the proportionality constant given by the Liouville measure of the domain and a certain deterministic constant which is computed explicitly and is, surprisingly, strictly greater than its Riemannian counterpart. Afterexplaining this result and its context, as well as some related estimates pertaining to the small-time behaviour of the heat kernel, I hope to also present a number of conjectures on the spectral geometryof LQG.These relate both to the behaviour of eigenfunctions (suggestingintriguing connections with so-called "quantum chaos") and to that of eigenvalues, for which we conjecture a connection to random matrixstatistics.This is joint work with Mo-Dick Wong (Durham).
17:15 • UZH Irchel, Winterthurerstrasse 190, Zürich, Building Y27, Room H12