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Calendar of Physics Talks Vienna
| Breaking bad theories of class S |
| Speaker: | Palash SINGH (University of Milano-Bicocca) |
| Abstract: | In this talk, I will discuss weakly-coupled descriptions of the typically non-Lagrangian 4d N=2 theories of class S, from the perspective of the 3d N=4 mirror duals of their circle compactifications. These descriptions often produce pathological configurations which I will relate to a corresponding notion of "badness" in the 3d N=4 theories. Leveraging some recent results regarding these 3d bad theories, I will introduce a new class of theories - broken theories - that naturally emerge in this setting. Building on these, I will present the systematic and analytic method that we have developed to determine the non-Lagrangian matter sectors and the weakly-coupled gauge groups in these frames, which arise dynamically via Higgsings triggered by operator vevs. |
| Date: | Tue, 09.12.2025 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-Lecture Hall, 1090 Vienna, Boltzmanngasse 5, 5th floor |
| Contact: | S. Fredenhagen, M. Sperling |
| Nitrogen Magneto-ionics for Data Security and Low-power Computing |
| Speaker: | Jordi Sort (ICREA Professor, Physics Department, Autonomous University of Barcelona, Spain) |
| Abstract: | Magneto-ionics âvoltage-driven modulation of magnetic properties via electric-field-induced ion transportâ offers a pathway toward low-power, analog magnetic memories and computing. Extending beyond conventional oxygen or lithium systems, this work introduces nitrogen magneto-ionics, where nitrogen ions migrate in transition metal nitrides (e.g., CoN, FeN, CoMnN, FeCoN) at room temperature using liquid or solid electrolytes [1â6]. These materials display tunable ferromagnetic, paramagnetic, and antiferromagnetic phases governed by alloy composition and nitrogen content [4]. Unlike oxygen-based systems, nitrogen transport proceeds through a uniform plane-wave-like front, favorable for multilayer memory architectures. We demonstrate voltage-driven magnetic switching with good reversibility, as well as neuromorphic behaviors such as synaptic potentiation/depression, and spike-timing-depende |
| Date: | Tue, 09.12.2025 |
| Time: | 15:00 |
| 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: | Prof. A. Fernández-Pacheco |
| Quantum Mechanics vs. Quantum Field Theory: What is different for infinitely many degrees of freedom?“ |
| Speaker: | Thomas Mannel (University of Siegen) |
| Abstract: | Quantum Field Theory (QFT) can be viewed a Quantum Mechanics (QM) with infinitely many degrees of freedom. This has interesting consequences, which at first sight seem to be mathematical details, but have far-reaching phenomenological consequences, which often are not well known to phenomenological practitioner. In this talk I will discuss this point and show a few examples, where this becomes relevant. |
| Date: | Tue, 09.12.2025 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-HS, Boltzmanngasse 5, 1090 Wien, 5.Stock |
| Contact: | A. Hoang, M. Procura, J. Pradler. H. Neufeld |
| Ernst Mach and the Vienna Circle |
| Speaker: | Philipp Leon Bauer (Austrian Academy of Sciences, University of Vienna) |
| Abstract: | Ernst Mach (1838-1916) was one of the most important natural scientists and philosophers of the nineteenth and twentieth centuries. Mach was also a pioneer for the history and philosophy of science, and his work has had a significant impact on the methodological development of various sciences. Mach’s principle of economy played an extremely important role in this regard. He argued that the task of natural science was, on the one hand, to put as many facts as possible into a clear form, and on the other hand, to present complicated facts in as few and simple elements as possible. He advanced the view that science primarily depends on simplicity and less thought effort. Coupled with Mach’s Pragmatism and Historicism, he made use of the principle of economy to advance a view of scientific research as a process in which theoretical terms and scientific theories are seen as auxiliary tools f |
| Date: | Wed, 10.12.2025 |
| Time: | 13:00 |
| Duration: | 45 min |
| Location: | Seminar room ZE-01-1 new Building ZE |
| Contact: | Paul Erker |
| Clock Spectroscopy on the Ionic Core of Alkaline-Earth Circular Rydberg Atoms |
| Speaker: | Marius Thomas (University of Stuttgart) |
| Abstract: | In recent years, highly excited Rydberg atoms trapped in optical tweezers have emerged as
a platform for quantum simulation and computing. However, they come with fundamental
restrictions, such as lifetime limited coherence times. We tackle this challenge by exciting
neutral 88Sr atoms into long-lived circular Rydberg states (CRS). At maximum orbital momentum,
fewer decay channels exist, and these can even be suppressed using a resonator
made from indium tin oxide (ITO). This results in CRS with lifetimes in the millisecond-range,
even at room temperature [1].
For the alkaline-earth species 88Sr, exciting the first valence electron to the CRS exposes
the second valence electron near the core. This provides access to a whole range of new
tools. The goal of my Master’s Thesis is to drive the 2S1/2 - 2D5/2 clock transition of the
ionic 88Sr+ core and perform spectroscopy on it.
In my talk, |
| Date: | Wed, 10.12.2025 |
| Time: | 16:15 |
| Duration: | 45 min |
| Location: | Helmut Rauch Hörsaal ATI |
| Contact: | Maximilian Prüfer |
| Optical detection of out-of-equilibrium spin accumulations in multilayers |
| Speaker: | Jon Gorchon (Université de Lorraine, CNRS, IJL, Nancy, F-54000, France) |
| Abstract: | Magneto-optical techniques are powerful tools for investigating ultrafast spin dynamics in magnetic materials [1,2] and are increasingly used to study spin and orbital angular momentum accumulation in magnetic/non-magnetic systems [3]. It was long believed that accumulation signals were much weaker than those from magnetization dynamics. Recently, we showed that under certain conditions these signals can match or even exceed magnetization signals during ultrafast demagnetization [4], and we demonstrated how to isolate them experimentally.
I will present experiments where we separate magnetization dynamics from spin accumulation. Accessing ultrafast spin accumulations enables identification of femtosecond laser–induced magnetization reversal mechanisms in multilayer stacks [5] and offers new means to probe angular momentum exchanges and transport properties. Moreover, these long propagati |
| Date: | Thu, 11.12.2025 |
| Time: | 11:00 |
| 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: | Prof. A. Fernández-Pacheco |
| Understanding, controlling and creating many-body systems atom by atom |
| Speaker: | Johannes Zeiher (LMU and Planq ) |
| Abstract: | Microscopic control and readout of individual quanta has been one of the driving forces behind advances in quantum science and technology in recent years, leading to spectacular breakthroughs across quantum simulation, quantum computing, quantum optics, and quantum metrology.
In my talk, I will present recent results on quantum-gas microscopy of many-body systems both in and out of equilibrium. In particular, I will discuss an experiment demonstrating strongly constrained out-of-equilibrium transport and the emergence of Hilbert space fragmentation in two-dimensional tilted Hubbard systems. In the second part of my talk, I will introduce a novel hybrid experimental platform based on the alkaline-earth atom strontium. By directly loading thousands of individually addressable atoms from a magneto-optical trap into an optical lattice, we achieve high-fidelity, low-loss imaging and iterativ |
| Date: | Fri, 12.12.2025 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | Helmut Rauch HÃÂÃÂÃÂörsaal ATI |
| Contact: | JÃÂÃÂÃÂörg Schmiedmayer |
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