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Calendar of Physics Talks Vienna
| Propagators in curved spacetimes from operator theory |
| Speaker: | Christian Gass (University of Vienna) |
| Abstract: | I will present two distinct operator-theoretic settings, which are useful for describing (or defining) propagators associated with a scalar Klein-Gordon field on a Lorentzian manifold M. The first setting is based on the Hilbert space of square integrable functions on M and leads to the definition of an "operator-theoretic Feynman propagator". The second setting is based on the Krein space of solutions of the Klein-Gordon equation and leads to a rigorous definition of two-point functions associated to two (possibly different) states. When M admits a reasonable definition of "out" and "in" states, the operator-theoretic Feynman propagator from the first setup typically corresponds to the time-ordered two-point function from the "in" to the "out" state in the second setup. After a general introduction, I will discuss several examples -- the one with the richest structure being de Sitter sp |
| Date: | Tue, 26.11.2024 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-Hoersaal, 1090 Vienna, Boltzmanngasse 5, 5th floor |
| Contact: | S. Fredenhagen, M. Sperling |
| Frontiers in Table Top Quantum Gravity |
| Speaker: | Marios Christodoulou (IQOQI Vienna) |
| Abstract: | Table Top Quantum Gravity nowadays colloquially refers to a forming interdisciplinary field that includes diverse contributions from theorists, experimentalists and philosophers alike across a range of disciplines from spacetime physics to quantum technologies. I discuss some of my contributions to the debate surrounding this nascent research field, while giving an overview of recent ideas and foundational issues that have arisen. |
| Date: | Wed, 27.11.2024 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Seminarraum A, Waehringer Strasse 17, 2nd Floor |
| Contact: | Piotr T. Chrusciel, David Fajman |
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