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Calendar of Physics Talks Vienna
| Fast Scrambling due to Rotating Shockwaves in Rotating Black Holes. |
| Speaker: | Rohan Poojary (TU Wien) |
| Abstract: | We study the perturbation due to rotating shockwaves in BTZ geometries at late times and analyse the change in Mutual Information between the two subsystems belonging to the dual CFT$_L$ and CFT$_R$.
We find that the scrambling of Mutual Information is in general governed by the Lyapunov index $\lambda_L$ which is bounded by $\kappa=\frac{2\pi}{\beta(1-\mu\mathcal{L})}\geq \frac{2\pi}{\beta}$ where $\mu=\rmi/\rpl$ and $\mathcal{L}$ is
the angular momentum of the shockwave. For the special case of $\mathcal{L}$=$1$ we find the Mutual Information analytically, characterized by $\lambda_L=\kappa/2$ and with the scrambling time for large black holes $t_*=\frac{\beta(1-\mu)}{\pi}\log S$.
If time permits I would also discuss consequences for the near horizon effective theory relevant to our observations. |
| Date: | Tue, 29.03.2022 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Sem.R. DA, gruen 05 (TU Wien, Freihaus) |
| Contact: | D. Grumiller, S. Fredenhagen, E. Battista, R. Ruzziconi |
| HLbL contribution to muon g-2 at short distances |
| Speaker: | Antonio Rodriguez (IJCLab, Paris) |
| Abstract: | One of the main contributions to theoretical uncertainties in muon g-2 comes from Hadronic Light-by-Light.
In order to achieve a significant reduction of them in the data-driven approach we need a better understanding of the different contributions from intermediate and high-energy regions.
In this talk I focus on the contributions associated to large loop momenta. It is shown how a precise Operator Product Expansion can be applied in this regime.
The massless quark loop is shown to give the leading order. Both gluonic corrections and power corrections are assessed. They are found to be numerically small.
The gluonic correction is found to be negative and the leading power correction is observed to scale as the pseudoscalar mass squared. The associated muon g-2 contributions are also displayed. |
| Date: | Tue, 29.03.2022 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Erwin-Schrödinger-Hörsaal, Faculty of Physics, Boltzmanngasse 5, 5. Stock ZOOM https://univienna.zoom.us/j/93427906843?pwd=YjhSejdUVW16QjVQYUh5TVNSNFNhQT09 Meeting ID: 934 2790 6843 Passcode: 073703 |
| Contact: | A. Hoang, M. Procura |
| Possible scale invariant effects in our low density Universe |
| Speaker: | Andre Maeder (Geneva) |
| Abstract: | An empty Universe would be scale invariant, as shown by both Maxwell equations and General Relativity.
The question arises on how much matter is necessary to break scale invariance in the Universe.
On the basis of scale invariant models based on expressions derived by Dirac (1973), we show that scale invariant effects rapidly decline
to zero for cosmological models with a density between zero and the critical one. For a density parameter Omega_m=0.3, some limited effects are remaining,
which correspond to the observed accelerated expansion. Several cosmological tests are consistent, e.g. the growth of density fluctuations is boosted in the scale invariant context,
a large M/L ratio is derived for clusters of galaxies, flat rotation curves are predicted in galaxies with a proper account of the radial acceleration relation (RAR). |
| Date: | Thu, 31.03.2022 |
| Time: | 15:00 |
| Duration: | 60 min |
| Location: | ZOOM https://univienna.zoom.us/j/6540036841?pwd=SytyVkZJZzNyRG9lMm13ejlHeHRRUT09 Meeting ID: 654 003 6841 Passcode: Gs4brS |
| Contact: | P. Chrusciel, D. Fajman |
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