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Calendar of Physics Talks Vienna
| On extensions of CMC-Bartnik data |
| Speaker: | Carla Cederbaum (Univ. Tübingen) |
| Abstract: | Bartnik data are a Riemannian 2-sphere of positive Gaussian curvature equipped with a non-negative function H to be thought of as its mean curvature in an ambient Riemannian 3-manifold. Mantoulidis and Schoen suggested a construction of asymptotically flat Riemannian 3-manifolds of non-negative scalar curvature which allows to isometrically embed given Bartnik data of vanishing mean curvature, i.e. H=0. They use their construction to explore — and disprove — stability of the Riemannian Penrose inequality. In collaboration with Cabrera Pacheco, McCormick, and Miao, we adapt their construction to constant mean curvature (CMC) Bartnik data, i.e. H=const.>0. Moreover, with Cabrera Pacheco and McCormick, we extend their construction to the asymptotically hyperbolic setting both for H=0 and for H=const.>0 Bartnik data. I will present the construction as well as the motivation for such a . . . |
| Date: | Mon, 25.06.2018 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Arbeitsgruppe Gravitation, Währinger Strasse 17, Raum 218, 2. Stock, 1090 Wien |
| Contact: | P.T. Chrusciel, D. Fajman |
| Fourfolds, integral Fluxes and Modularity |
| Speaker: | Thorsten Schimannek (Univ. Bonn) |
| Abstract: | Four-dimensional N=1 vacua of F-theory are determined by three discrete choices.
A topological type of elliptically fibered Calabi-Yau fourfolds, a choice of flux and
a minimum of the corresponding scalar potential. While there are several constructions that together provide an abundance of elliptic Calabi-Yaus, the choice of properly quantized flux is in general more involved. The talk will start with a brief review of
F-theory and the geometry of Calabi-Yau fourfolds. I will then explain how topological string theory and homological mirror symmetry can be used to determine properly quantized choices for a particular class of fluxes. Additional comments will be about certain Fourier-Mukai transformations that act on the underlying basis of topological branes and lead to modular properties of the Gromov-Witten potentials on non-singular Calabi-Yau fourfolds.
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| Date: | Tue, 26.06.2018 |
| Time: | 13:45 |
| Duration: | 60 min |
| Location: | TU Wien, Freihaus, SEM 136, 10. Stock, Wiedner Hauptstr. 8-10, 1040 Wien |
| Contact: | S. Fredenhagen, D. Grumiller, J. Knapp |
| A numerical formulation of resummation in effective field theory |
| Speaker: | Pier Monni (CERN) |
| Abstract: | I show how the resummation of infrared and collinear logarithms within Soft-Collinear Effective Theory (SCET) can be formulated in a way that makes it suitable for a Monte-Carlo implementation. This is done by applying the techniques developed for automated resummation using the branching formalism, which have resulted in the general resummation approach CAESAR/ARES. This work builds a connection between the two resummation approaches, and paves the way to automated resummation in SCET. As a case study I consider the resummation of the thrust distribution in electron-positron collisions at next-to-leading logarithm (NLL), and discuss the extension to more complicated observables and processes as well as to higher orders in the logarithmic accuracy. |
| Date: | Tue, 26.06.2018 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | A. Hoang, M. Procura |
| Global analysis for linear and nonlinear waves and the stability of Kerr-de Sitter space |
| Speaker: | Andras Vasy (Standford) |
| Abstract: | I will discuss the problem of proving the stability of the family of Kerr-de Sitter (KdS) black holes as solutions of Einstein's vacuum equation: spacetimes evolving from initial data close to those of $(M,g)$ stay globally close to $(M,g)$, and are indeed asymptotic to $(M,g)$ or another nearby member of the KdS family.
I will focus on analytic aspects of this problem together with the choice of a gauge to break the diffeomorphism invariance of Einstein's equation and the role of constraint damping. The analytic framework is that of global non-elliptic Fredholm problems. The main ingredients are, first, the microlocal control of the regularity of waves by means of elliptic, real principal type, and radial point estimates on a suitable compactification of the spacetime; and second, the asymptotic analysis in which model operators and resonance expansions play a role.
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| Date: | Fri, 29.06.2018 |
| Time: | 15:00 |
| Duration: | 60 min |
| Location: | Erwin-Schrödinger-Institut, Boltzmanngasse 9, Schrödinger Lecture Hall, 2. Stock |
| Contact: | A. Cap, P. T. Chrusciel, R. Donninger, M. Eichmair, M. Kunzinger |
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