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Calendar of Physics Talks Vienna
| MadNIS and the Road to MadGraph7 |
| Speaker: | Ramon Winterhalder (Universita degli Studi di Milano) |
| Abstract: | High-precision simulations based on first principles are a cornerstone of any modern physics research. For instance, as we approach the HL-LHC era, there is an ever-increasing demand for both accuracy and speed in simulations. Modern Machine Learning (ML) techniques are emerging as a beacon of hope, potentially diminishing the limitations of current methodologies and opening doors to uncharted territory in the parameter space. In this presentation, I will first explain the basic principles of machine learning and highlight current LHC event generation methodologies and their bottlenecks. Afterwards, I will delve into the MadNIS framework and illustrate how modern ML techniques can alleviate these limitations. In particular, I will present recent advancements in neural importance sampling, summarize the developments for differentiable event generators, and outline the future of MadGraph. |
| Date: | Mon, 12.05.2025 |
| Time: | 10:00 |
| Duration: | 60 min |
| Location: | Seminarroom 8 (5th floor) of the PSK |
| Contact: | Claudius Krause (HEPHY) |
| Speaker: | Konstantin WERNLI (University of Southern Denmark) |
| Abstract: | Topological Quantum Field Theories (TQFTs) were axiomatized by Atiyah as symmetric monoidal functors whose domain is a cobordism category. On the other hand, recently developed methods allow for perturbative quantization of field theories on manifolds with boundary.
I will review these concepts and then sketch a research program to build a bridge between them, discussing the example of Chern-Simons theory in some detail. One of the goals of this activity is to open new avenues towards the Asymptotic Expansion Conjecture. |
| Date: | Tue, 13.05.2025 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger Lecture Hall, 1090 Vienna, Boltzmanngasse 5, 5th floor |
| Contact: | S. Fredenhagen, M. Sperling |
| The Strong Interaction at 50 Years: Less Puzzling, More Rich, and Still Mysterious |
| Speaker: | Iain Stewart (MIT) |
| Abstract: | The strong interaction is described by a remarkable theory called Quantum Chromodynamics (QCD), a quantum field theory that is fully consistent at all distance scales and that gives rise to interesting emergent phenomena. It plays a crucial role in a variety of important physical processes, from binding together quarks and gluons in the proton, to the evolution of a hot-plasma of matter in the early universe, to producing streams of collimated particles called jets in high energy collisions. In this talk I will review what we have learned about QCD and its phenomena in the fifty years since its inception, as well as discussing the important role that control of QCD effects have on measuring the fundamental parameters of the standard model of particle and nuclear physics. To highlight the mysteries of QCD that remain unsolved, I will describe a top-10 list of important open questions. |
| Date: | Tue, 13.05.2025 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | Besprechungsraum 3A.1/2 in Postsparkasse, Georg-Coch-Platz 2, 1010 Wien |
| Contact: | Mukul Sholapurkar (HEPHY), David Dobrigkeit Chinellato (SMI) |
| Decoding the Standard Model with Flavour Physics |
| Speaker: | Marzia BORDONE (CERN) |
| Abstract: | During the last few years, significant progress has been achieved from the theoretical point of view to better understand and control predictions for flavour processes. These developments are crucial to be able to compare with the growing experimental accuracy stemming from the large datasets collected at the LHC and the Belle/Belle II experiments. Despite the efforts, some aspects are still not well known and require further scrutiny. I will review the status of some of the persisting puzzles and their impact on the search for Beyond the Standard Model effects. |
| Date: | Tue, 13.05.2025 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger Lecture Hall, 1090 Vienna, Boltzmanngasse 5, 5th floor |
| Contact: | A. Hoang, M. Procura |
| Topology and singularities in cosmological spacetimes satisfying the null energy condition |
| Speaker: | Walter SIMON (University of Vienna) |
| Abstract: | Inspired by the classical singularity theorems in General Relativity, Galloway and Ling (Commun. Math. Phys. 2017, 2024) have shown the following: If a globally hyperbolic spacetime satisfying the null energy condition contains a closed, spacelike Cauchy surface N which is strictly 2-convex (meaning that the sum of the lowest two eigenvalues of the future extrinsic curvature is positive), then N is either a spherical space or past null geodesically incomplete.
In recent work (with Eric Ling, Carl Rossdeutscher and Roland Steinbauer) we have relaxed the above convexity condition in essentially two respects. Firstly, we admit 2-convex extrinsic curvatures (for which the sum of the lowest two eigenvalues is non-negative). Secondly, if N admits a U(1) isometry group, we can impose even less restricive convexity conditions. In addition to spherical spaces and past null geodesically incomplete |
| Date: | Wed, 14.05.2025 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Seminarraum A, Waehringer StraÃe 17, 1090 Vienna, 2nd floor |
| Contact: | D. Fajman |
| Ferrimagnets: From THz emitters to skyrmions |
| Speaker: | Manfred Albrecht (Institute of Physics, University of Augsburg/Germany) |
| Abstract: | A new type of spintronic THz emitter has been discovered not too long ago, which is based on the inverse spin Hall effect. These âspintronicâ THz emitters typically consist of ferromagnetic/ nonmagnetic metal bilayers. We have shown that bilayers consisting of a ferrimagnetic (FI) Tb(Gd)-Fe alloys can be utilized as well as efficient spintronic THz emitters.
FI multilayers can also be used to host various magnetic spin textures including magnetic skyrmions, which are promising candidates for future spintronic devices. In this regard, we have shown the possibility to stabilize skyrmions and antiskyrmions in FI Gd/Fe based multilayers. With micromagnetic simulations, we concluded that the reduction of saturation magnetization and uniaxial magnetic anisotropy leads to the existence of a zoo of different spin objects and that they are primarily stabilized by dipolar interactions. Together w |
| Date: | Thu, 15.05.2025 |
| 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: | Prof. Dr. A. Fernandez-Pacheco |
| Observation of supersolid-like sound modes in a driven quantum gas |
| Speaker: | Nikolas Liebster (Universität Heidelberg) |
| Abstract: | Systems far from equilibrium can have radically different properties from the same system at equilibrium. A certain class of out-of-equilibrium systems are those where parameters are periodically driven in time. Though driving generically leads to heating, in certain cases it can produce ordered stationary states, enabling the successful application of mathematical descriptions developed for equilibrium scenarios. Bosonic quantum gases, for instance, have been shown to spontaneously develop self-stabilized, periodic density modulations when the two-particle interaction strength is driven in time. These patterned states share key physical properties to a seemingly different equilibrium physical system, namely supersolids. In this work, we probe the excitation spectrum of such a patterned state in a driven superfluid, finding that its response is identical to that of a one-dimensional supe |
| Date: | Fri, 16.05.2025 |
| Time: | 13:00 |
| Duration: | 45 min |
| Location: | Bibliothek Atominstitut |
| Contact: | Julian Léonard |
| Micro Arrays: a high throughput method for antibiotic screening |
| Speaker: | Michael Grunze (MPI für medizinische Forschung, Heidelberg/Deutschland) |
| Abstract: | Micro-patterned super-hydrophobic/ hydrophilic surfaces are used for medical diagnostics and drug screening. I will discuss the fabrication of these arrays with focus on oil infused hydrophobic surface. The infusion of oils into these surfaces creates so called SLIPS (slippery) surfaces which effectively suppress bacterial adhesion. Their preparation has been followed in situ by synchrotron holo-tomography with 50 nm resolution, showing the formation of a complex polymer/air/oil/water interface. Tests in contact with bacteria demonstrate their excellent-but limited- non-fouling properties. Bacterial film formation starts on defects and then covers the whole surface by first building bridges between defects in the SLIPS surface.
These micro-patterned super-hydrophobic/ hydrophilic surfaces are used to separate and prevent mixing of aqueous droplets confined in the hydrophilic areas. The |
| Date: | Fri, 16.05.2025 |
| Time: | 14:00 |
| 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. Dr. Gerhard Schütz |
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