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Calendar of Physics Talks Vienna
| Perturbative Quantization of Einstein-Hilbert Gravity |
| Speaker: | Klaus Sibold |
| Abstract: | In a perturbative approach Einstein-Hilbert gravity is quantized about a flat background. In order to render the model power counting renormalizable, higher order curvature terms are added to the action.
They serve as Pauli-Villars type regulators and require an expansion in the number of fields in addition to the standard expansion in the number of loops. Renormalization is then performed within the BPHZL scheme, which provides the action principle to construct the Slavnov-Taylor identity and invariant differential operators. After removal of the regulators, the final physical state space of the Einstein-Hilbert theory is realized via the quartet mechanism of Kugo and Ojima. Renormalization group and Callan-Symanzik equation are derived for the Green functions and, formally, also for the S-matrix. |
| Date: | Tue, 23.03.2021 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | The (recurring) BBB link is: https://moodle.univie.ac.at/mod/bigbluebuttonbn/guestlink.php?gid=x8o6ILSKJuC9 |
| Contact: | S. Fredenhagen, D. Grumiller, T. Schimannek |
| Core-level spectroscopy of transition metal oxides |
| Speaker: | Jan Kunes (TU Wien, Institut für Festkörperphysik) |
| Abstract: | Improving energy resolution of core-level photoemission (XPS) experiments in the past ten years has lead to the realization that valuable information about the valence electronic structure can be obtained by this seemingly atomic probe. Similar improvements in resonant inelastic x-ray scattering (RIXS) made this originally chemists’ tool (eV scale) a precious part of physicists’ toolkit (10 meV scale). I will present a computational approach for simulation of core-level spectra based on combination of dynamical mean-field theory with a postprocessing using a specially tailored exact diagonalization method. I will discuss applications of this approach to the calculation of XPS, RIXS and x-ray absorption spectra of selected transition metal oxides such as LaCoO3, V2O3 or monoxides NiO and MnO. |
| Date: | Tue, 23.03.2021 |
| Time: | 16:00 |
| Location: | TU Wien, The seminar will be held as a Zoom Meeting https://tuwien.zoom.us/j/96062751637?pwd=ZkRUWnlkUFFZb2pEdm55ZzFteTBNdz09 Meeting ID: 960 6275 1637 Passcode: 9ANd8XWj |
| Contact: | Univ.Prof.Dr. U. Diebold |
| The Coleman-Weinberg potential in multi-scale problems |
| Speaker: | Aneesh Manohar (UC San Diego) |
| Abstract: | Coleman and Weinberg (1973) gave the general formalism for computing quantum corrections to the effective potential, and showed how to renormalization-group improve the result. They discussed the case of a theory with a single scale. Effective field theory methods can be used to compute the potential in theories with multiple scales. There are some interesting new features which arise, which I will discuss in the talk.
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| Date: | Tue, 23.03.2021 |
| 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 |
| Stability of relativistic fluids on expanding cosmological spacetimes |
| Speaker: | Todd Oliynyk (Monash Univ., Australien) |
| Abstract: | In this talk, I will discuss recent results concerning the global stability to the future of solutions to the relativistic Euler equation on expanding cosmological spacetimes. The first part of the talk will be a review focusing on what is known about the stability and instability of relativistic fluids on cosmological backgrounds. In the second part of the talk, I will discuss new stability results for relativistic fluids with a linear equation of state p = Kρ on FLRW spacetimes where the equation of state parameter value K satisfies 1/3 < Κ < 1/2 . This new stability result is of particular interest because it was previously conjectured that instabilities should develop for the parameter values 1/3 < K < 1 . Time permitting, I will conclude the talk with a discussion of future projects and areas for further research. |
| Date: | Thu, 25.03.2021 |
| Time: | 11:00 |
| Duration: | 60 min |
| Location: | ZOOM https://univienna.zoom.us/j/6540036841?pwd=SytyVkZJZzNyRG9lMm13ejlHeHRRUT09 Meeting ID: 654 003 6841 Passcode: Gs4brS |
| Contact: | Piotr Chrusciel, David Fajman |
| Excitation spectra of scalar and gluonic systems far from equilibrium |
| Speaker: | Kirill Boguslavski (TU Wien) |
| Abstract: | Motivated by ultra-cold atom experiments and high-energy heavy-ion collisions, there has been a great effort in recent years to study scalar and gluonic systems far from equilibrium. Spectral functions extracted in classical-statistical lattice simulations have become a powerful tool in their analysis, and allow to identify the relevant dynamical processes nonperturbatively. In this talk, I will present results for scalar and gluonic systems. For scalar O(N) theories, we obtain a new classification of far-from-equilibrium universality classes. In gluonic plasmas, we find narrow quasiparticle peaks in 3+1 dimensions, while the structure of excitations in 2+1 dimensions is nontrivial and nonperturbative. |
| Date: | Fri, 26.03.2021 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | on-line |
| Contact: | Sebastian Erne |
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