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Calendar of Physics Talks Vienna
| Non-perturbative strings, asymptotic safety, and the swampland |
| Speaker: | Alessia Platania (Perimeter Institute) |
| Abstract: | Quantum gravity is undoubtfully one of the most important missing pieces in the understanding of the mathematical structure of our universe.The impossibility of consistently quantizing gravity via perturbative quantum field theory has led to a plethora of different proposals,
from asymptotically safe gravity to non-local gravity, loop quantum gravity,and string theory. Different approaches face different problems
and have succeeded in different areas. Yet,on the conceptual side,it is not obvious that all these frameworks are inequivalent or unrelated:
some theories may be low-energy approximations of others, or could even provide different mathematical descriptions of the same physics. On the technical side, the knowledge gained in an approach could be useful to investigate certain aspects of others. In this spirit, I will review progress in connecting and contrasting two theories |
| Date: | Tue, 25.04.2023 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | TU Sem.R. DA gruen 05 (Freihaus, TU Wien, Wiedner Hauptstrasse 8) |
| Contact: | S. Fredenhagen, D. Grumiller, E. Battista, R. Ruzziconi |
| Mathematical aspects of the FOPT/CIPT discrepancy in tau decays |
| Speaker: | Dr. Nestor Gonzalez Gracia (Univ. Salamanca, Univ. Wien) |
| Abstract: | The long-standing discrepancy between fixed-order (FOPT) and contour-improved (CIPT) perturbative expansions for hadronic spectral function moments
in the context of tau decays leads to systematic discrepancies in the determination of the strong coupling and contributes to its theoretical uncertainty.
We address the FOPT and CIPT series from the mathematical perspective. FOPT, which is a power expansion in the strong coupling, is compared to CIPT,
which in contrast is an expansion in functions of the strong coupling. We find important differences in the formal properties that both series have as
asymptotic expansions, and we also gain insight on the apparent better behavior of CIPT at low orders. |
| Date: | Tue, 25.04.2023 |
| Time: | 16:15 |
| Location: | Erwin-Schroedinger Lecture Hall, Faculty of Physics, Boltzmanngasse 5, 5th floor |
| Contact: | A. Hoang |
| Surface Organometallic Chemistry for Controlled Functionalization and Molecular Understanding of Surfaces: Supported Single-Site Catalysts and Beyond |
| Speaker: | Christophe Copéret (Department of Chemistry and Applied Biosciences â ETH Zürich, Switzerland) |
| Abstract: | Homogeneous and heterogeneous catalysts have, each, specific advantages. While homogeneous catalysts are typically associated with efficient chemical transformations at low temperatures (high selectivity) and molecular understanding of catalytic events (structure â activity relationship), heterogeneous systems are typically preferred in term of process intensification (easier regeneration and separation processes). Here, we will show how it is possible to combine the advantages of homogeneous and heterogeneous catalysts by the controlled functionalization of the surfaces of oxide materials and the characterization of surface species at the molecular level, thus allowing more predictive rational approaches [1a, 1b]. We will illustrate the power of this approach with the development of well-defined âsingle-sitesâ focusing in the first part on olefin metathesis catalysts [2], whose performa |
| Date: | Wed, 26.04.2023 |
| Time: | 15:00 |
| Location: | TU Wien, Institut für Angewandte Physik, E134 1040 Wien, Wiedner HauptstraÃe 8-10 Green Tower âAâ, 2nd floor, SEM.R. DA grün 02 B - GEO |
| Contact: | Univ.Prof. Dr. Ulrike Diebold |
| Can we observe non-perturbative vacuum shifts in cavity QED? |
| Speaker: | Rocio Saez Blazquez (TU Wien, Atominstitut) |
| Abstract: | In recent years, vacuum-induced modifications of molecular properties have regained considerable attention in the context of cavity QED, where the coupling of matter to individual electromagnetic modes is strongly enhanced by a tight confinement of the field. It has been speculated that under such ultrastrong coupling conditions, the electromagnetic vacuum could change the rate of chemical reactions or modify work functions, phase transitions and (super-)conductivity, even without externally driving the cavity mode.In this work we investigate the ground state energy shift of a single dipole due to its coupling to the electromagnetic vacuum in a confined geometry and address the fundamental question of whether or not it is possible to achieve conditions under which the light-matter coupling can result in non-perturbative corrections to the dipoleâs ground state. To do so we consider two s |
| Date: | Wed, 26.04.2023 |
| Time: | 16:15 |
| Duration: | 45 min |
| Location: | Hörsaal ATI |
| Contact: | Sebastian Erne |
| X-ray Spectroscopy and Mars Sample Return: A Tale for Four Generations of Mars Rovers |
| Speaker: | Scott Van Bommel (Washington University in St. Lous) |
| Abstract: | Since the Alpha Proton X-ray Spectrometer on the 1997 Sojourner rover, X-ray spectrometers have flown on every successful NASA Mars rover mission. The Sojourner, Spirit, Opportunity, Curiosity, and Perseverance Mars rovers have provided key data that continues to shape our understanding of Mars. While orbital assets provide broad-scale information of the martian surface, rovers have proven key to elucidating our understanding of Marsâ paleoclimate and evolution to present day. X-ray spectrometers such as the Alpha Particle X-ray Spectrometer (APXS) on Spirit, Opportunity, and Curiosity, and the Planetary Instrument for X-ray Lithochemistry (PIXL) on Perseverance, have been instrumental in seeking out signs of past water, assessing ancient habitability, and selecting ideal samples to be cached on the martian surface.
This presentation will discuss the evolution of Mars rover X-ray spectr |
| Date: | Thu, 27.04.2023 |
| Time: | 10:00 |
| Location: | TU Mainbuilidng, Karlsplatz 13 |
| Contact: | Hartmut Abele and Irina Pradler |
| Some rigidity results for compact initial data sets |
| Speaker: | Abraao Mendes (Maceio, Brasil) |
| Abstract: | In this lecture, we aim to present some rigidity results for compact initial data sets, in both the boundary and no boundary cases.
For example, under natural energy, boundary, and topological conditions, we obtain a global version of a well-known result of H. Bray, S. Brendle, and A. Neves.
We also prove some extensions of results obtained, in a previous work, by M. Eichmair, G.J. Galloway, and the author. Finally, as time permits, we are going
to present a number of examples in order to illustrate some of the results presented in this lecture. This is part of a joint work with G.J. Galloway. |
| Date: | Thu, 27.04.2023 |
| Time: | 15:30 |
| Duration: | 60 min |
| Location: | via 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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