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Calendar of Physics Talks Vienna
| When does separation of variables work? Applications to black hole spacetimes. (Vienna Theory Lunch Seminar) |
| Speaker: | Finnian Gray (Universität Wien) |
| Abstract: | Separation of variables is one of the most common ansaetze to study partial differential equations, particularly in physics. However, it is less common to ask when and why this is possible. I will discuss the geometric characterization of the separation of variables and the relation to conserved quantities due to explicit and hidden symmetries. I will then discuss how this applies to and has advanced our understanding of the physics of particles and fields in black hole spacetimes.
[[This talk is part of the "Vienna Theory Lunch Seminar", a weekly seminar aimed at both graduate and advanced undergraduate students, jointly organized by the University of Vienna and TU Wien. The focus of the seminar is on recent theoretical research done by Master students, PhDs and PostDocs. Free lunch (pizza) will be provided at the seminar. More information: https://lunch-seminar.univie.ac.at ]] |
| Date: | Tue, 24.10.2023 |
| Time: | 12:30 |
| Duration: | 75 min |
| Location: | Boltzmanngasse 5, 5th floor, Schrödinger Lecture Hall |
| Contact: | Florian Lindenbauer |
| Weyl-Ambient Metrics, Obstruction Tensors and Their Roles in Holography (Joint Theory Seminar) |
| Speaker: | Weizhen Jia (University of Illinois) |
| Abstract: | Weyl geometry is a natural extension of conformal geometry with Weyl covariance mediated by a Weyl connection. We generalize the Fefferman-Graham (FG) ambient construction for conformal manifolds to a corresponding construction for Weyl manifolds. We first introduce the Weyl-ambient metric motivated by the Weyl-Fefferman-Graham (WFG) gauge, which is a generalization of the FG gauge for asymptotically locally AdS (AlAdS) spacetimes. Then, the Weyl-ambient space as a pseudo-Riemannian geometry induces a codimension-2 Weyl geometry. Through the Weyl-ambient construction, we investigate Weyl-covariant quantities on the Weyl manifold and define Weyl-obstruction tensors. We show that Weyl-obstruction tensors appear as poles in the Fefferman-Graham expansion of the AlAdS bulk metric for even boundary dimensions. [...] |
| Date: | Tue, 24.10.2023 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Online (ZOOM). Link : https://tuwien.zoom.us/j/67102039242?pwd=ZHhS |
| Contact: | Adrien Fiorucci, Daniel Grumiller |
| The status of naturalness II |
| Speaker: | Gian Giudice (CERN) |
| Abstract: | Naturalness arguments have been a powerful guiding principle for
physicists as they try to construct new theories. When applied to our
current description of the microscopic world in terms of quantum field
theory, naturalness leads to the apparent paradox of the smallness of
the electroweak scale and the cosmological constant, as compared to the
Planck scale. The hypotheses on which naturalness rests, the
consequences of relaxing some of these hypotheses, and the current
attempts to develop new paradigms beyond naturalness will be discussed.
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| Date: | Tue, 24.10.2023 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Fakultaet fuer Physik, Erwin Schroedinger-HS, Boltzmanngasse 5, 5. Stock |
| Contact: | A. Hoang, H. Neufeld, M. Procura |
| Quasilocal corrections to Bondi's mass loss formula and dynamical horizons |
| Speaker: | Albert Huber (Vienna) |
| Abstract: | In my talk, a null geometric approach to the quasilocal Brown-York formalism will be used to calculate, within a bounded gravitating physical system,
the flux of energy through a dynamical horizon of a non-stationary spacetime.
This is done by varying the total Hamiltonian of the system (bulk part plus boundary part) so as to derive an integral law describing the rate of change
of mass and/or radiant energy escaping through the dynamical horizon.
The results obtained in this way, as is shown, lead to previously unrecognized correction terms, including a bulk-to-boundary inflow term that leads to corrective extensions
of Einstein's quadrupole formula in the large sphere limit and to quasilocal corrections to Bondi's mass-loss formula, the latter occurring in the null geometric context. . . . . |
| Date: | Wed, 25.10.2023 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Vera Hoftrakt - Victor-Franz-Hess-seminar room, WaehringerstraÃe 17 |
| Contact: | P. Chrusciel, D. Fajman |
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