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Calendar of Physics Talks Vienna
| BPHZ renormalization in combinatorially non-local field theory |
| Speaker: | Johannes Thürigen (Universität Münster) |
| Abstract: | Combinatorial non-locality occurs in various field theories such as non-commutative field theory, matrix and tensor theories or the group field theory approach to quantum gravity. Though interactions in such theories are not point-like, they are still local in the sense that for any divergent Feynman diagram there is a unique counter term vertex, described in general by a graph. This allows to generalize the renormalization Hopf algebra of Feynman graphs to a Hopf algebra of 2-graphs which gives a concise algorithm for applying Zimmermann’s forest formula to amplitudes in any renormalizable non-local field theory. |
| Date: | Tue, 18.05.2021 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Combinatorial non-locality occurs in various field theories such as non-commutative field theory, matrix and tensor theories or the group field theory approach to quantum gravity. Though interactions |
| Contact: | S. Fredenhagen, D. Grumiller, T. Schimannek |
| Semileptonic b decays, their puzzles and opportunities |
| Speaker: | Paolo Gambino (Università di Torino) |
| Abstract: | The semileptonic decays of the b hadrons observed at the B factories and at LHCb are an important testing ground for the Standard Model.
Beside a well-known hint for lepton flavour universality violation in the tau channels, other puzzling tensions have appeared over the years
that are however unlikely to signal new physics. I will review their status and the efforts towards their resolution. |
| Date: | Tue, 18.05.2021 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | https://univienna.zoom.us/j/93104933847?pwd=N0FrL0E1UHlkQWRhQTlQODVkZ3kvUT09 Meeting ID: 931 0493 3847 Passcode: 674625 |
| Contact: | A. Hoang, P. Stoffer |
| Stable Big Bang formation |
| Speaker: | Grigorios Fournodavlos (Paris) |
| Abstract: | In this talk we will investigate the past dynamics of cosmological solutions to Einstein's equations, containing a Big Bang singularity.
More precisely, we will focus on the classical generalized Kasner examples. The celebrated ``singularity'' theorem of Hawking states
that the past of sufficiently small perturbations of such solutions is causally geodesically incomplete. However, it is not in general known
whether such a degeneracy is related to the formation of a curvature singularity. In many cases, unstable dynamics are predicted,
which adds to the difficulty of the problem. We will discuss a recent joint work with I. Rodnianski and J. Speck that classifies the behavior of perturbed solutions in the so-called subcritical regime.
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| Date: | Thu, 20.05.2021 |
| Time: | 15:00 |
| Duration: | 60 min |
| Location: | https://univienna.zoom.us/j/6540036841?pwd=SytyVkZJZzNyRG9lMm13ejlHeHRRUT09 |
| Contact: | Piotr Chrusciel, David Fajman |
| Calabi-Yau metrics: what are they good for? |
| Speaker: | Anthony Ashmore (Chicago U. & Paris LPTHE) |
| Abstract: | Calabi-Yau manifolds have played a key role in both mathematics and physics, and are particularly important for deriving realistic models of particle physics from string theory. Unfortunately, very little is known about the explicit metrics on these spaces, leaving us unable, for example, to compute particle masses or couplings in these models. I will review recent progress in this direction on using numerical approximations to compute the metric and the (p,q)-form Laplacian on these spaces. I will finish with some examples of what one can do with this new "data". |
| Date: | Thu, 20.05.2021 |
| Time: | 16:30 |
| Duration: | 60 min |
| Location: | https://tuwien.zoom.us/j/95482849369?pwd=SkU2WU5hMVJBQWsyVlFXRlRvQlIvdz09 |
| Contact: | Laura Donnay, Niccolo Cribiori |
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