Calendar of Physics Talks Vienna

Two-dimensional photoactive frameworks: towards dynamic covalent chemistry and exciton imaging
Speaker:Laerte Patera (University of Innsbruck)
Abstract:Combining structural tunability, chemical stability with a crystalline structure, covalent organic frameworks (COFs) are promising material platforms for a wide range of applications in (photo-) catalysis. Two-dimensional COFs, composed of a single atomic layer, exhibit peculiar opto-electronic properties, making them suitable platforms for light-induced up-conversion of chemicals. However, despite the growing interest in such 2D polymers, their synthesis is still a major challenge. A proposed approach relies on dynamic covalent chemistry, where the chemical equilibrium is tuned to enable reversible bond formation, allowing the polymer networks to overcome kinetic limitations and reach the crystalline configuration. Here, I will describe the application of near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) to elucidate the reversible formation of a two-dimensional boroxine
Date: Mon, 04.12.2023
Time: 17:00
Location:Uni Wien, Kolingasse 14-16, Seminar Room 9, and on Zoom
Contact:Dr. Stefan Uttenthaler

TQFTs, HQFTs and other category theoretical approaches to quantum field theory (Vienna Theory Lunch Seminar)
Speaker: Paul Grosskopf (Université libre de Bruxelles)
Abstract: Topological Quantum Field Theories (short: TQFTs) are mathematical toy models for quantum field theory. Coming from physics they quickly sparked interest with mathematicians, not only because they lead to new topological invariants for manifolds or knots. Going back to Atiyah the most common formulation uses category theory to describe d-dimensional TQFTs as functors from the d-bordism category to some symmetric monoidal category, most noteably the category of vector spaces and linear maps. Many variations of these have developed over the years, such as Homotopy Quantum Field Theories (HQFTs), open/closed TQFTs or defect TQFTs. [...] [[part of the "Vienna Theory Lunch Seminar, see https://lunch-seminar.univie.ac.at ]]
Date: Tue, 05.12.2023
Time: 12:30
Duration: 75 min
Location:University of Vienna, Boltzmanngasse 5, 5th floor, Schrödinger Lecture Hall
Contact:Florian Lindenbauer

AdS/Yang Mills: from QCD to Composite Higgs
Speaker:Nicholas Evans (University of Southampton)
Abstract:I discuss a programme to describe the chiral symmetry breaking dynamics and spectra of all asymptotically free non-supersymmetric gauge theories using holography. Our holographic description inputs the perturbative running of the gauge theory to motivate the non-perturbative running of the anomalous dimensions of operators. The dynamics and spectra are then predicted. In addition we use Witten's multi-trace prescription to include strongly coupled NJL four fermion interactions. Masses and mass splittings require a full non-abelian flavour structure and a bulk higgs mechanism. Examples of interesting theories are: QCD where the spectra can be systematically improved by higher dimension operators (in the spirit of "perfection" on the lattice) and predictions made for exotics such as the sexaquark mass; theories with multiple fermion representations where large mass gaps between [...]
Date: Tue, 05.12.2023
Time: 14:00
Duration: 60 min
Location:Fakultaet fuer Physik, Erwin Schroedinger-HS, Boltzmanngasse 5, 5. Stock
Contact:Adrien Fiorucci, Daniel Grumiller

Scanning Kelvin Probe technique to investigate hydrogen uptake under atmospheric corrosion conditions
Speaker:Flavien Vucko (Institut de la Corrosion, Brest/France & RISE Research Institutes of Sweden, Materials and Production, Corrosion Department, Kista/Sweden)
Abstract:During service life, vehicles can be exposed to severe corrosive conditions, particularly in the presence of different salts. Corrosion of steel and its metallic protective coating can lead to hydrogen uptake into the steel, which can induce hydrogen embrittlement, particularly in high strength steels. Historically, the permeation method was used to evaluate the hydrogen flux under cathodic charging conditions in a solution. This method was extended to investigate the hydrogen permeation under atmospheric corrosion conditions too. The main advantage of the permeation is its capability to detect and quantify very low hydrogen fluxes. However, the drawback is the absence of lateral resolution, which leads to an averaging of the hydrogen flux from the process area. One alternative under atmospheric conditions is the use of the Scanning Kevin Probe (SKP) that shows some lateral resolution. S
Date: Tue, 05.12.2023
Time: 16:00
Location:TU Wien, Institut für Angewandte Physik, E134 1040 Wien, Wiedner Hauptstraße 8-10 Yellow Tower „B“, 5th floor, SEM.R. DB gelb 05 B
Contact:Univ.Prof. Dr. M. Valtiner

Electroweak and Finite-Lifetime Corrections for Boosted Top Quark Production
Speaker:Daniel Lechner (University of Vienna)
Abstract:Jet mass measurements for processes involving boosted top quark pair-production at the HL-LHC or future lepton colliders are a very promising tool for high-precision measurements of the top quark mass in a well-defined renormalization scheme. Apart from including QCD corrections and resummations, for which well-developed frameworks exist, eventually also electroweak and finite-lifetime effects need to be accounted for systematically. For boosted top quark initiated inclusive jets we apply an electroweak Soft-Collinear-Effective-Theory (SCET) framework that allows for a coherent resummation of electroweak Sudakov and rapidity logarithms and finite-lifetime effects together with large logs from QCD. Apart from double-top-resonant effects, the factorization approach can also account for single-resonant effects, which are related to the interference of final states originating from top quark
Date: Tue, 05.12.2023
Time: 16:15
Duration: 60 min
Location:Fakultaet fuer Physik, Josef Stefan-HS, Boltzmanngasse 5, 3. Stock
Contact:A. Hoang, M. Procura

Design and Development of a Degenerate Cavity for Dispersive Imaging of Ultracold Atoms
Speaker:Oliver Lueghamer (TU Wien, Atominstitut)
Abstract:Most measurements performed on ultracold atoms are of a destructive single time nature. We present an approach for an enhanced operation of dispersive imaging techniques. To reach this goal we want to use a degenerate cavity which allows the probe beam to pass the sample multiple times. Degenerate cavities were already used in quantum microscopy to surpass the shot noise limit without the use of delicate quantum states. For this mostly biological investigations, a pulsed laser operation was employed. Only recently continuous wave applications were implemented experimentally. In my master project I develop and test such a degenerate cavity setup for the potential use in the consisting atom chip experiment. We are able to show a signal to noise ratio (SNR) enhancement for large biological samples (e.g. epithelial cells of a human cheek). In collaboration with Thomas Juffmann we are also in
Date: Wed, 06.12.2023
Time: 16:15
Duration: 45 min
Location:Helmut Rauch Hörsaal ATI
Contact:Maximilian Prüfer