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Calendar of Physics Talks Vienna
| Aspects of generalized symmetries from string theory: symmetry theories and generalized charges |
| Speaker: | Fabio Apruzzi (University of Padova) |
| Abstract: | Symmetries are crucial in any physical system, as they define the theoretical model that describes it. For instance, symmetries play a fundamental role in quantum field theory (QFT), both in defining the QFT and in constraining its dynamics. The full power of symmetries has only been exploited very recently through the introduction of a generalized notion of symmetry. For example, generalized symmetries have been used to theoretically describe many phases of QFT in terms of symmetry realization, such as confinement. This generalization hinges on recognizing that the notion of conservation extends to the topological nature of the symmetry operator. It leads to higher-form symmetries, higher groups, and non-invertible symmetries.In my talk, I will first introduce how these symmetry structures are conveniently described by a (d+1)-dimensional topological field theory, whose topological defe |
| Date: | Tue, 19.11.2024 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | online on Zoom |
| Contact: | S. Fredenhagen, M. Sperling |
| Entanglement and Bell non-locality in high-energy collision |
| Speaker: | Marco Fabbrichesi (INFN Trieste) |
| Abstract: | Quantum tomography, the study of quantum states and their properties, has increasingly been used in high-energy physics as a tool for testing Bell inequalities and constrain new physics. I will describe some recent results in B-meson and charmonium decays and the ongoing work on top-quark, tau-lepton and gauge boson production. |
| Date: | Tue, 19.11.2024 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-Hoersaal, 1090 Vienna, Boltzmanngasse 5, 5th floor |
| Contact: | A. Hoang, M. Procura |
| NEC angle in critical collapse |
| Speaker: | Daniel Grumiller (TU Wien) |
| Abstract: | We identify a new critical parameter in Choptuik's gravitational collapse: the angle at which null energy condition (NEC) saturation lines intersect at the center of the critical spacetime. These NEC lines coincide with regions of vanishing curvature, dividing spacetime into stripes of positive and negative curvature. By numerically solving Choptuik's original system we find the NEC angle to be \alpha=0.64 (about 37 degrees) and analytically derive \alpha=2\arccot(D-1) for any spacetime dimension D>3. |
| Date: | Wed, 20.11.2024 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Seminarraum A, Waehringer Strasse 17, 2nd Floor |
| Contact: | Piotr T. Chrusciel, David Fajman |
| New approach to conserved charges of generic gravity in AdS |
| Speaker: | Emel Altas (Karamanoglu Mehmetbey University, Turkey) |
| Abstract: | Starting from a divergence-free, rank-4 tensor, which yields the cosmological Einstein tensor after contracting its indices and which has the symmetries of the Riemann tensor, we give a construction of conserved charges in Einstein's gravity and its higher derivative extensions for asymptotically anti-de Sitter spacetimes. In this construction, not only the conserved charges but also the current four vector yielding the charge are explicitly gauge-invariant, and the charge expression involves the linearized Riemann tensor.
Also, constructing an identity using the same divergence free tensor, we provide two ways to compute the surface gravity and Hawking temperature of a stationary black hole. In one of these methods we gave the Hawking temperature in terms of three volume integral of Gauss-Bonnet invariant in the total region outside the event horizon. |
| Date: | Thu, 21.11.2024 |
| Time: | 17:00 |
| Duration: | 60 min |
| Location: | TU Wien, Freihaus, Seminar room on the 10th floor |
| Contact: | Daniel Grumiller, Iva Lovrekovic |
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