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Calendar of Physics Talks Vienna
| Charges, conserved quantities and fluxes in de Sitter spacetime |
| Speaker: | Aaron Poole (Southampton U.) |
| Abstract: | In this talk I will discuss conserved quantities in asymptotically locally de Sitter (dS) spacetimes, motivated by the broader aim of a developing a fully nonlinear understanding of the nature of gravitational waves in dS. I will begin with a review of the asymptotics of dS spacetimes, before showing that one can use the tools of the covariant phase space formalism (together with analytic continuation of analogous results in anti-de Sitter spacetime) in order to derive expressions for spatially conserved charges and temporally conserved quantities corresponding to boundary isometries. For spacetimes admitting no such isometries, I will present flux formulae which capture the effects of outgoing gravitational radiation and illustrate these via application to exact solutions, with particular emphasis on the Robinson-Trautman dS class. |
| Date: | Tue, 10.05.2022 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Sem.R. DA, gruen 05 (TU Wien, Freihaus) |
| Contact: | D. Grumiller, S. Fredenhagen, E. Battista, R. Ruzziconi |
| The SMEFT program at the LHC |
| Speaker: | Ilaria Brivio (Universität Heidelberg) |
| Abstract: | The LHC experiments are entering a precision era, where the sensitivity to indirect effects of new physics, i.e. discrepancies between data and SM predictions,
will increase substantially. Searches for these signals are most conveniently performed within the framework of the Standard Model Effective Field Theory (SMEFT),
that allows to implement a very ambitious program: a systematic search for inconsistencies with SM predictions in a large number of different processes, from which
"agnostic" information about new physics can be extracted via a combined SMEFT interpretation. I will review the current status of this effort, that has seen important
theoretical and experimental advancements in recent years. I will focus in particular on the complementarities between Higgs, electroweak and top quark processes
and on the implications for the interpretation in terms of concrete BSM scenarios. |
| Date: | Tue, 10.05.2022 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | ZOOM https://univienna.zoom.us/j/93427906843?pwd=YjhSejdUVW16QjVQYUh5TVNSNFNhQT09 Meeting ID: 934 2790 6843 Passcode: 073703 |
| Contact: | A. Hoang, M. Procura |
| Collisionless Vlasov gas around black holes |
| Speaker: | Patryk Mach (Cracow) |
| Abstract: | I will discuss accretion of collisionless Vlasov gas onto a Schwarzschild black hole. An equivalent of the Bondi flow (steady spherically symmetric accretion) has been developed by Paola Rioseco and Olivier Sarbach in 2017. In this case,the gas is assumed to be at rest at infinity, where it is described by the Maxwell-Juttner distribution.
Last year, together with Andrzej OdrzywoÅek, we computed an equivalent of the so-called Bondi-Hoyle model (accretion onto a moving black hole).
I will discuss some details of this model and compare them to the results obtained in the ballistic approximation. If time permits I will comment on possible generalizations to the Kerr geometry. |
| Date: | Thu, 12.05.2022 |
| Time: | 15:00 |
| Duration: | 60 min |
| Location: | Gravitationsphysik: Seminarraum A - Währinger Strasse 17, 2. Stock ZOOM https://univienna.zoom.us/j/6540036841?pwd=SytyVkZJZzNyRG9lMm13ejlHeHRRUT09 |
| Contact: | P. Chrusciel, D. Fajman |
| Flat JT Gravity and the Schwarzian of BMS2 (Cancelled) |
| Speaker: | Blagoje Oblak (Ecole Polytechnique, CPHT and Paris, LPTHE) |
| Abstract: | This talk is devoted to Jackiw-Teitelboim (JT) gravity in Bondi gauge with vanishing cosmological constant. The asymptotic symmetries of the theory span an infinite-dimensional group dubbed `BMS2' (for Bondi-Metzner-Sachs in two dimensions), but most of the existing literature reduces this group to its warped Virasoro subgroup. I shall argue that one can avoid this reduction and use the BMS2 group throughout. In particular, the boundary action of the system is a BMS-Schwarzian with an extra zero-mode, and its partition function is one-loop exact with respect to the Haar measure on BMS2. The peculiarities of BMS2 are pointed out, including the fact that it has a single coadjoint orbit at fixed central charges. Allowing for a natural complexification affects this feature sharply, suggesting that more work is required to fully understand the phase space of asymptotically flat JT gravity. |
| Date: | Thu, 12.05.2022 |
| Time: | 16:30 |
| Duration: | 60 min |
| Location: | Freihaus, Sem.R. DB gelb 09 |
| Contact: | Iva Lovrekovic, Romain Ruzziconi |
| Controlling the behaviour of quantum emitters by shaping their environment |
| Speaker: | Daniel Malz (Max-Planck-Institut, DE) |
| Abstract: | Quantum optics describes few-level emitters (e.g. atoms) coupled to bosonic fields (e.g. photons). When emitters are placed in regular arrays, this can dramatically alter their properties. I will discuss how this can be exploited for applications, such as detection of photons, emission of entangled photonic states, or quantum simulation with light. In the end I will talk about novel physical effects in this paradigmatic setup that can occur when the underlying bosonic field becomes lossy and is described by a non-Hermitian Hamiltonian. |
| Date: | Fri, 13.05.2022 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | ATI Hörsaal/https://tuwien.zoom.us/j/93672218922?pwd=dEZNQ2liVzRNNURvNmVWVE5KUWRiQT09 |
| Contact: | Peter Rabl |
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