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Calendar of Physics Talks Vienna
| An asymptotic framework for gravitational scattering |
| Speaker: | Geoffrey Compere (ULB) |
| Abstract: | I will first review the main difficulties in defining scattering in the presence of gravity.
I will then outline some concepts useful at defining scattering in asymptotic Minkowski spacetime:
a puzzle-piece diagram with 5 asymptotic expansions and 4 overlapping regions that faithfully describe massless and massive fields.
I will show in which sense particles, stars and black holes can be described with the same tools in a unified way.
I will discuss the BMS covariance that inevitably occurs when gravitational radiation is present and contrast when is BMS symmetry important
(to define memory effects) and when it can be bypassed (to define invariant Lorentz charges and intrinsic spin of bodies).
I will finally discuss infrared divergences and propose how to regulate them. |
| Date: | Tue, 02.05.2023 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger Lecture Hall, Faculty of Physics, Boltzmanngasse 5, 5th floor |
| Contact: | D. Grumiller, S. Fredenhagen, E. Battista, R. Ruzziconi |
| Hidden Symmetries and Separability in Rotating Black Hole Spacetimes |
| Speaker: | Finnian Gray (University of Vienna) |
| Abstract: | Stationary Rotating black holes have two kinds of symmetries. The explicit kind which are generated by their timelike and rotation Killing vectors, and the hidden ones which come from Killing tensors.These symmetries are very useful for simplifying physical equations because they allow one to apply a separation of variables ansatz decoupling the PDEs into a set of ODEs.
In this talk I will review the general theory of separability in this context and how it applies to the Kerr--NUT--AdS class of spacetimes in any dimension, and moreover to SuGra and string theory inspired black holes. In these cases,the hidden symmetries all descend from one object called the principal tensor.
As applications I'll discuss:
1) The separability of Massive vector fields in these spacetimes and the use for e.g. quasi-normal modes
2) the new hidden symmetries of a generic class of slowly rotating black holes |
| Date: | Thu, 04.05.2023 |
| Time: | 15:00 |
| Duration: | 60 min |
| Location: | TU Wien, Freihaus, Seminar room 10th floor |
| Contact: | Iva Lovrekovic |
| Testing the gravity-quantum interface with optomechanics and quantum memories |
| Speaker: | Dennis Raetzel (Berlin) |
| Abstract: | It has become one of the major endeavors in physics to understand the interplay between two of our most successful theories, quantum mechanics and general relativity. These efforts have to be guided by experiments and observations at the interface of the two theories. In this talk I will present two specific examples of experimental proposals:
a)A potential route to obtain evidence for quantized gravity by employing gravitationally coupled quantum optomechanical sensors [1].
b)An investigation of the effect of gravitational time dilation on photonic states stored in quantum memories [2]. I will also discuss the prospects to perform the corresponding experiments with near-future technology.[1] Plato, A. D. K., Rätzel, D., & Wan, C.(2022). Enhanced Gravitational Entanglement in Modulated Optomechanics. arXiv:2209.12656.
[2]Barzel, R., GündoÄan, M., Krutzik, M., Rätzel, D.,& Lämmerzahl C. |
| Date: | Thu, 04.05.2023 |
| Time: | 15:30 |
| Duration: | 60 min |
| Location: | via zoom https://univienna.zoom.us/j/6540036841?pwd=SytyVkZJZzNyRG9lMm13ejlHeHRRUT09 |
| Contact: | P. Chrusciel, D. Fajman |
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