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Calendar of Physics Talks Vienna
| Higher-Spin Gravity in Three-Dimensional Flat Space (Vienna Theory Lunch Seminar) |
| Speaker: | Philipp Neckam (TU Wien) |
| Abstract: | Theories of interacting massless fields of spin larger than two naturally emerge in the high-energy limit of string theory. When including gravity, these theories also serve as toy models to investigate the holographic AdS/CFT correspondence in a more controlled setting. While it has long been known that the existence of such theories is strongly restricted by various no go theorems, in three dimensions none of these results apply, thus providing an ideal setting to study higher-spin gravity. Even so, the investigation of three-dimensional metric-like higher-spin gravity theories has been initiated only recently in 2018, and the work discussed here is a continuation of these efforts. The Noether-procedure is generalized to three dimensions, taking into account the influence of dimension-dependent-identities. [ full abstract and more information: https://lunch-seminar.univie.ac.at ] |
| Date: | Tue, 14.01.2025 |
| Time: | 12:15 |
| Duration: | 75 min |
| Location: | TU Wien: Wiedner Hauptstr. 8-10, yellow area, 10th floor, seminar room DB10E11 |
| Contact: | Florian Lindenbauer |
| Topological features in lattice models |
| Speaker: | Vincentas Mulevicius (University of Vienna) |
| Abstract: | In this talk I will give an introduction to simple lattice systems having topological properties, in particular the Kitaev's toric code and its generalisations - the Levin-Wen models. Using these models as an example we will also discuss topological phases of matter and how they are related with quantum memory, quantum computing and topological quantum field theories.
If time permits, I will also describe the role of non-invertible symmetries in these models and how they can be used to `engineer' new topological phases out of a given one.
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| Date: | Tue, 14.01.2025 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-HS, Boltzmanngasse 5, 1090 Wien, 5.Stock |
| Contact: | S. Fredenhagen, M. Sperling |
| Characterizing the Fischer-Tropsch Reaction over Flat and Stepped Cobalt Single Crystals at 1bar |
| Speaker: | Patrick Lömker (Department of Physics, Stockholm University Stockholm/Sweden) |
| Abstract: | Industrial catalysis is both societally relevant for the products attainable through it (i.e., fertilizer, fine chemicals and fuels) and transforming rapidly as a direct consequence to climate change and the reevaluation of resources together with CO2 emissions in general. This also brings about the need to design catalysts that can work under lower pressures (i.e.,1bar) and at lower temperatures, which fits ideally to the virtual pressure cell in the POLARIS setup [1].
In my talk I will present a study of intermediates during the Fischer-Tropsch reaction over two single crystal surfaces of Co(0001) and Co(101 Ì
4). Herein we employ the Stockholm University POLARIS setup located at P22, DESY, PETRA III.
Our findings indicate that the Co surface remains metallic at all conditions with only adsorbed species. There are a number of different intermediates on the surface such as adsorbed CO i |
| Date: | Tue, 14.01.2025 |
| Time: | 16:00 |
| Location: | TU Wien, Institut für Angewandte Physik, E134 1040 Wien, Wiedner HauptstraÃe 8-10 Yellow Tower âBâ, 5th floor, SEM.R. DB gelb 05 B |
| Contact: | Univ.Prof. G. Parkinson |
| The quality/cosmology tension for a post-inflationary QCD axion |
| Speaker: | Zhiquan Sun (MIT) |
| Abstract: | It is difficult to construct a post-inflation QCD axion model that solves the axion quality problem (and hence the Strong CP problem) without introducing a cosmological disaster. Firstly, generic solutions to the quality problem complicates the solution to the cosmological domain wall problem, leading to a cosmology where domain walls dominate the energy density of the universe. Secondly, post-inflation axion models also face a potential problem from fractionally charged relics; solving this problem often leads to low-energy Landau poles for Standard Model gauge couplings, reintroducing the quality problem. We study several examples, finding that models that solve the quality problem face cosmological problems, and vice versa. Successful examples may have a nonstandard cosmological history, undermining the widespread expectation that the post-inflation QCD axion scenario predicts a uniqu |
| Date: | Tue, 14.01.2025 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-HS, Boltzmanngasse 5, 1090 Wien, 5.Stock |
| Contact: | A. Hoang, M. Procura |
| Probing gluon saturation via diffractive jet production in photon-nucleus interactions |
| Speaker: | Edmond IANCU (IPhT, Saclay) |
| Abstract: | Hadronic interactions at high energy are controlled by a dense form of partonic matter, known as the Colour Glass Condensate (CGC), which is mostly made with gluons and whose main characteristic is the phenomenon of gluon saturation: the gluon occupation numbers are large, of order $1/\alpha_s$, but they cannot grow any further, due to strong mutual repulsion. Given its high density, this gluon matter is weakly coupled, which opens the way to first principles calculations of hadronic cross-sections. Yet, despite an accumulation of data (at HERA, RHIC and the LHC) which are globally consistent with expectations from the CGC, the onset of saturation â which occurs in a limited window of transverse momenta â has never been directly observed. We propose a new process which is particularly promising in that sense: the diffractive production of jets in high-energy hadronic interactions... |
| Date: | Thu, 16.01.2025 |
| Time: | 16:00 |
| Location: | TU Wien Freihaus (Wiedner HauptstraÃe 8-10), Sem.R. DB gelb 05 A |
| Contact: | Markus Leuthner |
| Searching for new physics with ultracold molecules |
| Speaker: | Michael Tarbutt (Imperial College) |
| Abstract: | In the Standard Model of particle of physics, the electron has a tiny permanent electric dipole moment (EDM). In most theories that extend the Standard Model, this EDM is predicted to be many orders of magnitude larger due to new CP-violating mechanisms. Thus, EDM measurements are searches for new CP-violating physics which is deeply connected to the puzzle of the matter-antimatter asymmetry of the Universe. The most precise measurements of the electron EDM all use molecules. The molecules are spin polarized, and the EDM determined by measuring the spin precession frequency in an applied electric field. The precession is due to the interaction of the EDM with an effective electric field which can be exceptionally large for heavy polar molecules. To reach high precision we need long spin precession times, which is only possible with neutral molecules if they are cooled to microkelvin temp |
| Date: | Fri, 17.01.2025 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | Helmut Rauch Lecture Hall |
| Contact: | Tim Langen |
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