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Calendar of Physics Talks Vienna
| Observables vs. gauge symmetries: lessons from the quasi-local approach |
| Speaker: | Wolfgang Wieland (IQOQI Vienna) |
| Abstract: | An introduction to the loop representation to non-perturbative quantum gravity will be given.
The talk will focus on the quasi-local approach and explain the distinction between observables, symmetries and gauge symmetries in the context of classical and quantum general relativity.
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| Date: | Tue, 01.12.2020 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | https://moodle.univie.ac.at/mod/bigbluebuttonbn/guestlink.php?gid=x8o6ILSKJuC9 |
| Contact: | Thorsten Schimannek |
| On Gromov’s conjecture of fill-ins with nonnegative scalar curvature (II) |
| Speaker: | Yuguang Shi (Hong Kong) |
| Abstract: | Let (Σn−1, γ, H) be an orientable n−1 -dimensional Riemannian manifold, H be a positive function on Σ.One of basic problems in Riemannian geometry is to ask: under what conditions is it that γ is induced by a Riemannian metric g with nonnegative scalar curvature for example defined on Ωn and H is the mean curvature of Σ in Ω with respect to the outward unit normal vector?Recently, M.Gromov proposed several conjectures relate to this problem.In this talk, I will discuss the relation of this problem with the positive mass theorem, and present my recent work on this which joints with Dr.Wang Wenlong, Dr.Wei Guodong，and Zhu Jintian. The talk with the same title was delivered in“Virtual Workshop on Ricci and Scalar Curvature in honor of Gromov" in this July,I will give proofs of some results which were not given in the previous talk. This talk is based on https://arxiv.org/pdf/2007.06756.pdf |
| Date: | Thu, 03.12.2020 |
| Time: | 10:00 |
| Duration: | 60 min |
| Location: | joint relativity/differential geometry seminar by ZOOM https://zoom.us/j/92376135485?pwd=LzlUemhvcU5rL0hhZGxPOUVieDgxZz09 |
| Contact: | Piotr Chrusciel, David Fajman |
| Geometric formulation of covariant phase methods with boundary |
| Speaker: | Juan Margalef-Bentabol (Universidad Complutense de Madrid) |
| Abstract: | In physics, one standard way to study and understand a theory is through its dynamical formulation. Whenever possible, this is obtained by considering some initial conditions and evolving them through the dynamical equations of the theory. One gets then a curve over the space of initial conditions which codifies the evolution. This approach is useful in many settings, including General Relativity (ADM, numerical relativity, gravitational waves...), however, it also has some limitations. Namely, to understand some non-local concepts such as black holes and their properties (e.g. spin, energy, or entropy) one runs into some complications. Another approach is to study the space of solutions where each point represents a whole solution of the theory. For well-posed problems, this space is equivalent to the space of initial conditions (each initial condition gives rise to one and only one sol |
| Date: | Thu, 03.12.2020 |
| Time: | 16:30 |
| Duration: | 60 min |
| Location: | https://tuwien.zoom.us/j/95482849369?pwd=SkU2WU5hMVJBQWsyVlFXRlRvQlIvdz09 |
| Contact: | Laura Donnay, Céline Zwikel |
| The search for new physics below the GeV-scale: two showcases |
| Speaker: | Josef Pradler (Hephy) |
| Abstract: | In this talk, I will highlight the diverse phenomenology that enters in our quest to find new physics, and in particular Dark Matter, when the associated mass-scale is at or below the GeV scale. Two showcases are presented: first, we shall explore the viability of a scalar Dark Matter particle that that has been contemplated as a solution to the muon g-2 anomaly as well as an explanation for the excess of 511 keV photons observed in the Galactic center. Second, we shall consider a fermionic dark state for which the ordinary photon becomes the new physics messenger. We study both scenarios from the viewpoints of cosmology, astrophysics, high-intensity beams, Standard Model precision tests, and Dark Matter direct detection. |
| Date: | Fri, 04.12.2020 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | on-line |
| Contact: | Jochen Schieck |
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