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Calendar of Physics Talks Vienna
| The full bosonic string as a geometric variational problem |
| Speaker: | Volker Branding (Uni Wien) |
| Abstract: | In this talk we will focus on the action functional of the full bosonic string (the Polyakov action together with a two-form and a scalar potential) as a geometric variational problem.
We will study the existence of critical points, which correspond to solutions to the classical Euler-Lagrange equations for the full bosonic string. We will derive existence results for the case that the domain is either a closed Riemannian surface or two-dimensional Minkowski space and the target a compact Riemannian manifold. If time permits we will point out the mathematical problems that arise when extending the previous analysis to the superstring action.
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| Date: | Tue, 14.03.2017 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | S. Fredenhagen, H. Steinacker |
| Towards the realisation of fusion energy reactors: The edge of magnetically confined, tokamak plasmas and its stability |
| Speaker: | Dipl.-Ing. Florian laggner (TU Wien, IAP) |
| Abstract: | The performance of a magnetically confined, fusion plasma is strongly impacted by the plasma edge, which is the boundary between the hot, confined plasma and the reactor walls. In a tokamak reactor, which uses a toroidally axis-symmetric magnetic field configuration, a regime of improved plasma confinement, the so-called H-mode, has been observed. The improvement of plasma confinement origins from a transport barrier at the plasma edge, which is accompanied by steep gradients of the plasma pressure, named pedestal. The maximum sustainable pressure gradient at the plasma edge is usually set by an ideal magnetohydrodynamic limit, which if exceeded is leading to edge localized modes (ELMs) that relax the pedestal. The mechanisms setting the final pedestal structure (height and width) are not fully understood. Here, microturbulent instabilities are expected to become
important. The presented |
| Date: | Tue, 14.03.2017 |
| Time: | 16:00 |
| Location: | Technische Universität Wien, Institut für Angewandte Physik, E134 yellow tower „B“, 5th floor, Sem.R. DB gelb 05 B (room number DB05L03), 1040 Wien, Wiedner Hauptstraße 8-10 |
| Contact: | Univ.Prof.Dr. Friedrich Aumayr |
| Charged lepton decays from soft flavour violation |
| Speaker: | Elke Aeikens (Univ. Wien) |
| Abstract: | im Rahmen des Seminars für Teilchenphysik |
| Date: | Tue, 14.03.2017 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | W. Grimus |
| Strong-Field Waveform Sampling for Probing Attosecond Dynamics in Solids |
| Speaker: | Shawn Sederberg (Max Planck Institute of Quantum Optics, Garching) |
| Abstract: | Resolution of temporal dynamics requires an event that is sufficiently localized in time relative to the dynamics themselves. Extreme ultraviolet (XUV) attosecond pulses provide the shortest electromagnetic flashes and can be used to resolve sub-femtosecond electron dynamics in matter. In this approach, the large ionization potential of the noble gas to be ionized temporally confines emission of the XUV spectrum of interest to a single peak of the driving electric field. The large bandgap energy of common electrical insulators provides a similar opportunity for extreme temporal localization when irradiated by sub-2-cycle near- to mid-infrared laser pulses. In this case, the high-order nonlinearity of interband excitations acts as a narrow temporal gate on the laser pulse envelope, confining excitations to a sub-femtosecond timescale (A. Schiffrin et al., Nature 493, 70-74 (2013)). … |
| Date: | Wed, 15.03.2017 |
| Time: | 14:15 |
| Location: | TU Wien, Institute for Theoretical Physics, Seminar room DB gelb 10, Wiedner Hauptstraße 8 – 10, B (yellow tower), 10th floor |
| Contact: | Univ.Prof. Dr. Joachim Burgdörfer |
| Introduction to Topological Insulators and Superconductors (Part 2) |
| Speaker: | Prof. Benoit Doucot (LPTHE, Paris-6) |
| Abstract: | In these lectures, I will present some of the important concepts in this field, starting from the Quantum Hall effect, and several of its two-dimensional extensions by Haldane and Kane and Mele. Then, I will discuss the "bulk-edge correspondence" which plays a crucial role for the possible applications of these topological systems. Finally, I will present the key ideas behing the ten-fold classification. These lectures will be self-contained, and mostly with a pedagogical goal. |
| Date: | Wed, 15.03.2017 |
| Time: | 16:00 |
| Duration: | 90 min |
| Location: | 10th floor seminar room in yellow tower of TU Wien Freihaus (Wiedner Hauptstrasse 8-10, A-1040 Vienna) |
| Contact: | Ayan Mukhopadhyay |
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