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Calendar of Physics Talks Vienna
| Quantum-limited measurements for open quantum simulators |
| Speaker: | Maximilian Prüfer (Atominstitut, TU Wien) |
| Abstract: | Quantum measurements are typically implemented by coupling an isolated system to an auxiliary meter. Weak, repeated measurements therefore offer a promising route toward controllable open quantum simulators. I will present tunnel-coupled superfluids as a platform for simulating quantum fields, where optimal control techniques enable the preparation of tunable, entangled initial states. A quantum-limited generalized measurement scheme is introduced to probe quantum properties and dynamics. Finally, I will discuss progress toward implementing repeated and continuous local measurements, paving the way for fully controllable open quantum simulators.
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| Date: | Tue, 18.11.2025 |
| Time: | 12:15 |
| Duration: | 60 min |
| Location: | TU Wien (TU): Wiedner Hauptstr. 8-10, green area, 5th floor, seminar room DA05E10 |
| Contact: | Ivor Kresic |
| Gamma5 in dimensional regularization - progress on non-anticommuting gamma5 and gauge-invariance restoration |
| Speaker: | Dominik STOECKINGER (TU Dresden) |
| Abstract: | Dimensional regularization is a key method used in Feynman diagrammatic computations in elementary particle theory. Since its earliest days, however, it has been known that the Gamma5 matrix is notoriously difficult to define in D dimensions. The traditional BMHV scheme goes back to the earliest proposals by 't Hooft and Veltman and employs a non-anticommuting gamma5. Its advantage is full mathematical consistency and the existence of all-order proofs. Its disadvantage is the spurious breaking of gauge invariance in chiral gauge theories like the electroweak standard model. In our research programme we determine the required finite counterterms needed to restore gauge invariance, to allow more straightforward applications of the BMHV scheme in future practical calculations in the EWSM and beyond... |
| Date: | Tue, 18.11.2025 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-Lecture Hall, 1090 Vienna, Boltzmanngasse 5, 5th floor |
| Contact: | A. Hoang, S. Fredenhagen, M. Procura, M. Sperling |
| Charged Helium Nanodroplets: A Cold Laboratory for Molecular Ions and Astrochemistry |
| Speaker: | Dr. Elisabeth Gruber (Department of Ion Physics and Applied Physics, University Innsbruck) |
| Abstract: | Helium nanodroplets provide a highly versatile and unique environment for trapping and cooling dopant species to ultralow temperatures. In particular, highly charged helium droplets open exciting new avenues for investigating fundamental physical and chemical processes. In recent studies, we are examining how charges are distributed within individual droplets and how these charges can act as nucleation sites for the formation of molecular and cluster ions, as well as larger nanoparticles, all within a single droplet.
In this talk, I will focus on the use of highly charged helium droplets for the efficient formation of helium-tagged molecular ions, which enables high-resolution electronic and vibrational spectroscopy of cold molecular ions [1]. This approach allows us to obtain precise absorption spectra of astrochemical relevant ions, with a particular emphasis on carbonaceous species su |
| Date: | Tue, 18.11.2025 |
| 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: | Prof. Dr. Richard Wilhelm |
| Synthetic Lorentzian geometry |
| Speaker: | Roland STEINBAUER (University of Vienna) |
| Abstract: | Spacetimes arising in general relativity often exhibit non-smooth features that challenge traditional differential geometric approaches to Lorentzian geometry. In Riemannian geometry, synthetic approaches, especially triangle comparison and optimal transport methods, have extended curvature concepts beyond smooth manifolds. Recent work has established the foundations for an analogous synthetic Lorentzian geometry based on the fundamental notion of Lorentzian length spaces. These spaces capture the essential causal structure of spacetime without requiring smoothness or a manifold structure at all. In this talk, we explain the basics of this new geometry, outline initial results including comparison theorems and convergence results, and explore potential applications in general relativity and discrete approaches to quantum gravity. |
| Date: | Wed, 19.11.2025 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | VERA Seminar Room (Viktor-Franz-Hess Lecture Hall), Waehringer Straße 17, 1090 Vienna, Hoftrakt, 1st floor |
| Contact: | D. Fajman |
| Towards fault tolerant quantum computation through code teleportation |
| Speaker: | Andrzejewski, Tomasz (TU Wien Atominstitut) |
| Abstract: | QEC codes have different capabilities: qLDPC codes have a high encoding rate but are not particularly useful for processing while topological codes have poor encoding rate but high thresholds and allow for fault-tolerant quantum computation through code switching or magic state injection. These differences may be exploited by storing information in a dedicated quantum memory while performing computation on a quantum processor. The ideal memory code should be noise resistant (high distance, bias-tailored), such that quantum information can be stored for a long time, while having a high encoding rate to maintain resource efficiency. Processor codes should be small and allow for (easily implementable and resource-efficient) fault-tolerant gates. Ideally, the memory-processor combination should enable universal fault-tolerant quantum computation. In this talk we consider experiments demonstr |
| Date: | Wed, 19.11.2025 |
| Time: | 16:15 |
| Duration: | 45 min |
| Location: | Helmut Rauch Hörsaal ATI |
| Contact: | Maximilian Prüfer |
| Potential Shaping Using a DMD for Injection of Topological Edge Modes with Ultracold Atoms |
| Speaker: | Carlo Daniel (LMU Munich) |
| Abstract: | In this seminar, I will present the results of my MasterâÂÂs thesis on the development and characterization of an optical setup based on a Digital Micromirror Device (DMD) for generating high-fidelity, spatially tailored optical potentials aimed at the injection of topological edge modes in a cold-atom quantum simulator.
The motivation for this work arises from the need for energy-selective preparation of edge states in a Floquet-engineered honeycomb lattice. In current experiments, a Bose-Einstein condensate of 39K atoms is released from a tightly focused optical tweezer near a potential step, a method that lacks the spectral resolution required for selective loading of topological edge modes. To address this limitation, a DMD-based projection system was designed to generate box-like attractive potentials with homogeneous interior, allowing for controlled population of edge modes within a |
| Date: | Thu, 20.11.2025 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | Seminar room ZE-01-1 Building ZE ATI |
| Contact: | Uros Delic |
| Composition of (quantum) communication protocols |
| Speaker: | Ramona Wolf (University of Siegen ) |
| Abstract: | Proving that a (quantum) information-processing protocol is secure is already a demanding task. Yet, in realistic settings such as quantum communication networks or distributed cryptographic systems these protocols rarely stand alone; they are typically embedded within larger communication networks that integrate both classical and quantum components. One might expect that if each piece of such a network is secure on its own, the entire system should be secure as well. Surprisingly, this intuition can fail: Seemingly harmless combinations of secure building blocks can create unexpected vulnerabilities, revealing gaps in our understanding of security. In this talk, I will explore how such pitfalls arise and illustrate them with concrete examples. I will then discuss recent approaches to overcoming these issues and achieving robust, composable security in complex networks. |
| Date: | Fri, 21.11.2025 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | Helmut Rauch Hörsaal ATI |
| Contact: | Glaucia Murta |
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