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Calendar of Physics Talks Vienna
| Moduli stabilization and search for dS vacua in type IIA strings compactified on rigid CY threefolds |
| Speaker: | Prof. S. V. Ketov (Tokyo Metropolitan University and Kavli IPMU, the University of Tokyo) |
| Abstract: | Flux compactifications of type IIA strings on rigid Calabi-Yau threefolds are studied by taking into account both perturbative and non-perturbative (instanton) quantum corrections. The low-energy
effective action, given by the gauged N=2 supergravity in four space-time dimensions, is computed after neglecting back reaction and NS5 instantons. The axion stabilization is achieved due to D-instantons, but dS vacua and viable inflation are not found. |
| Date: | Mon, 07.05.2018 |
| Time: | 13:00 |
| Duration: | 60 min |
| Location: | TU Wien, Freihaus, SEM 136, 10. Stock, Wiedner Hauptstraße 8-10, 1040 Wien |
| Contact: | Timm Wrase |
| Speaker: | Andreas Braun (Oxford U.) |
| Abstract: | Compact manifolds with the exceptional holonomy groups G_2 and Spin(7)
can be used in M-Theory to geometrically engineer theories in 4D and 3D
with minimal supersymmetry. Building on new results in mathematics, we
review recent progress in the construction of such geometries, the associated physics, and dualities to other string compactifications. |
| Date: | Mon, 07.05.2018 |
| Time: | 15:45 |
| Duration: | 60 min |
| Location: | SEM 136, TU Wien, Freihaus, 10th floor (Wiedner Hauptstr. 8-10, A-1040 Vienna) |
| Contact: | Daniel Grumiller |
| Curvature squared invariants in 6D N=(1,0) supergravity |
| Speaker: | Gabriele Tartaglino-Mazzucchelli (KULeuven) |
| Abstract: | I will review the recent construction of new curvature squared supersymmetric invariants for off-shell N=(1,0) supergravity in six dimensions. Their construction is based on a non-trivial interplay between the superconformal tensor calculus, the superform approach to construct supersymmetric invariants and novel off-shell superspace techniques. The new invariants include the 6D Gauss-Bonnet combination which is linked to the description of alpha'-corrections to the low-energy limit of compactified string theory. I will then comment on applications of these results. |
| Date: | Tue, 08.05.2018 |
| Time: | 13:45 |
| Duration: | 60 min |
| Location: | TU Wien, Freihaus, SEM 136, 10. Stock, Wiedner Hauptstr. 8-10, 1040 Wien |
| Contact: | S. Fredenhagen, D. Grumille, J. Rosseel |
| Observation of Magnetite Surface Dynamics and Reactivity by FastSTM |
| Speaker: | Barbara A.J. Lechner (Technische Universität München, Department Chemie, Garching/Germany) |
| Abstract: | A chemical reaction on a catalyst surface is typically a highly dynamic process: reactants are activated on the catalyst particle and can spill over onto the support material, molecules move across the surface, products form and desorb, and the catalyst surface itself can restructure. Thus, the reaction rate is influenced, e.g. through mass transport limitations, while the durability of a catalyst depends on the stability of the catalyst particles and support under reaction conditions. We investigate such dynamic phenomena on the magnetite, Fe3O4(001), surface using scanning tunneling microscopy (STM).
To obtain a new, in situ, view of dynamic surface processes, we have accelerated our STM to video frame rates [1]. In the case of magnetite [2], we observe mobility of the surface itself at temperatures up to 100°C. Typical surface defects which appear similar topographically in STM can be |
| Date: | Tue, 08.05.2018 |
| 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. Ulrike Diebold |
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