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Calendar of Physics Talks Vienna
| Deformations of JT Gravity and KdV Equations |
| Speaker: | Joshua Kames-King (University of Bonn) |
| Abstract: | Recently, it was shown that the duality of double-scaled matrix models and JT gravity can be extended to include surfaces with conical defects.
We show that the thermal partition function of this deformed theory may be written as the free energy of topological gravity around a shifted expansion point.
By use of the KdV equation we furnish an off-shell description for both the single and multi-boundary cases of the partition function.
We also rewrite the deformed partition function as a low temperature expansion, which allows for a convenient calculation of contributions up to a desired order.
We use this approach to demonstrate the existence of a Hawking-Page phase transition between connected and disconnected surfaces for this instance of JT gravity. Furthermore, we calculate the spectral form factor and compare with the standard JT case. We conclude by commenting on the dS2 case. |
| Date: | Tue, 19.01.2021 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | https://moodle.univie.ac.at/mod/bigbluebuttonbn/guestlink.php?gid=x8o6ILSKJuC9 |
| Contact: | S. Fredenhagen, D. Grumiller, T. Schimannek |
| QED effects in rare B meson decays |
| Speaker: | Martin Beneke (TU München) |
| Abstract: | The exponentiation of soft photon radiation is a classic result of QED, but for QED effects of objects with structure
a more general approach is required. In this seminar I discuss how modern methods of effective field theory and
factorization (more familiar for the strong interaction) result in a systematic treatment of QED effects in decays of
B mesons to a lepton pair, or a pair of light mesons, including the summation of large logarithms.
On top of adding precision, QED offers surprises: for B -> mu mu, the QED correction is enhanced in heavy-quark power counting,
and reveals that the process is no longer a pure annihilation decay. |
| Date: | Tue, 19.01.2021 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | The seminars start at 16:15 but the meetings will be open already at 16:00. The link will be provided via email by Simon Plätzer (simon.plaetzer@univie.ac.at) |
| Contact: | A. Hoang, M. Procura, S. Plätzer |
| Conformal Einstein's equations |
| Speaker: | Wojciech Kaminski (Warsaw) |
| Abstract: | Vanishing of the Fefferman-Graham obstruction tensor was proposed by Anderson and Chrusciel as a tool for studying asymptotically simple solutions to Einstein's equations. It is a conformally covariant equation and a stronger condition: every lambda-vacuum solution in any even dimension has vanishing Fefferman-Graham tensor. The equation is an alternative for known Friedrich's construction of conformal version of Einstein's equations. This approach will work if one can show that the equation is hyperbolic. I will discuss the proof in my talk. |
| Date: | Thu, 21.01.2021 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | ZOOM - https://zoom.us/j/92376135485?pwd=LzlUemhvcU5rL0hhZGxPOUVieDgxZz09 |
| Contact: | Piotr Chrusciel, David Fajman |
| Searches for new interactions at Belle II |
| Speaker: | Gianluca Inguglia (HEPHY Institut für Hochenergiephysik der ÖAW) |
| Abstract: | The standard model of particle physics (SM) is a theoretical framework that describes fundamental interactions and constituents of matter. Although very successful in predicting phenomena, in recent years experiments worldwide have reported tensions arising from anomalies observed in the decays of B mesons and in properties of leptons. Most of these tensions strongly point towards new interactions which treat, unlike the SM, leptons of different generations or flavors differently. Such kind of interactions are said to violate lepton flavor universality (LFUV) and might also be the link between ordinary and dark matter (DM). I will discuss an approach to the solution of this problem based on the analysis of the data collected by the Belle II detector at the Super-KEKB, the world's “brightest” particle accelerator. Three unique searches and some of their by-products will be presented: a se |
| Date: | Fri, 22.01.2021 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | on-line |
| Contact: | Jochen Schieck |
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