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Calendar of Physics Talks Vienna
| Local operations in Quantum Field Theory: rethinking relativistic causality |
| Speaker: | Maria Papageorgiou (OEAW, IQOQI) |
| Abstract: | Recent developments in local measurement theory for Quantum Field Theory (QFT) offer new perspectives on relativistic causality. The representation of dynamics in such theories imposes crucial constraints on local (rather than asymptotic) quantum measurements and their signalling properties. Sorkin's 'impossible measurements' scenario demonstrates that microcausality alone is insufficient to prevent superluminal signalling in relativistic quantum theories employing Lüders' state update rule. This raises fundamental questions about local operations and their interpretation in QFT.
In this talk, we examine how recently developed measurement theories—particularly detector-based approaches and the Fewster-Verch framework in algebraic QFT—address these challenges. We adopt the local S-matrix formalism and utilise a hierarchy of factorisation conditions that exclude superluminal signalling and |
| Date: | Tue, 21.04.2026 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-HS, Boltzmanngasse 5, 1090 Wien, 5.Stock |
| Contact: | S. Fredenhagen, M. Sperling |
| Muon decay: From the Michel parameters over LEFT and SMEFT to BSM |
| Speaker: | Jakob MORITZ (University of Vienna) |
| Abstract: | How would a heavy new field from beyond the Standard Model leave its imprint on a process like muon decay that happens well below the electroweak scale? In order to bridge the energy regimes and investigate the traces of new physics within the phenomenology of muon decay, we perturb the Michel parameters in the presence of Low Energy Effective Field Theory (LEFT) operators. To infer their UV origin, we collect the matching Standard Model Effective Field Theory (SMEFT) operators at dimension six. Finally, we open them up and ask: Which possible Beyond Standard Model (BSM) fields could produce them? Focusing on one specific BSM scalar field, we derive the constraints imposed by precision measurements of muon decay. This approach synthesizes experimental data and effective field theory matching into a comprehensive exploration of energy scales and theoretical layers. |
| Date: | Tue, 21.04.2026 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger Lecture Hall, 1090 Vienna, Boltzmanngasse 5, 5th floor |
| Contact: | A. Hoang, J. Pradler, M. Procura |
| Localized Surface Plasmon Controlled Chemistry at and beyond the Nanoscale |
| Speaker: | Nan Jiang (University of Illinois Chicago, Dept. of Chemistry & Dept. of Physics Chicago, IL/USA) |
| Abstract: | Our research focuses on materials at the single-molecule and atomic scale, investigating how local environments govern the physical and chemical properties of functional materials, nanostructures, and surface-supported molecular systems with Ångström-scale resolution. Tip-Enhanced Raman Spectroscopy (TERS) uniquely integrates the atomic spatial resolution of Scanning Tunneling Microscopy (STM) with the chemical sensitivity of Raman spectroscopy. By utilizing a plasmonically active scanning probe, the Raman signal at the tip-sample junction is greatly enhanced, enabling single-molecule probing. When combined with ultrahigh vacuum conditions, this approach allows atomistic control of localized surface plasmons with exceptional stability and precision. Using TERS, we have achieved: (1) single-molecule chemical identification;1 (2) quantum-level characterization of adsorbate-substrate intera |
| Date: | Wed, 22.04.2026 |
| Time: | 11:00 |
| Location: | TU Wien, Institut für Angewandte Physik, E134 1040 Wien, Wiedner Hauptstraße 8-10 Yellow Tower „B“, 1st floor, Fachgruppenraum Physik, DB01E15 Zoom-link: https://tuwien.zoom.us/j/68788957002?pwd=0SG2 |
| Contact: | Dr. Jan Balajka |
| The quantum energy outflux emerging from a collapsing shell |
| Speaker: | Noa Zilberman (Princeton University) |
| Abstract: | When a compact object collapses to form a black hole, quantum field theory predicts the emission of an energy outflux to future null infinity, which later relaxes to Hawking radiation.
Within the semiclassical framework, we derive a simple, closed form, analytical expression for the energy outflux emitted from a spherical thin null shell collapsing to form a black hole. In particular, this energy outflux vanishes (quadratically in r-2M) as the shell approaches the horizon. This result refutes claims that the Hawking energy outflux originates from the collapsing body, showing instead that it develops in a broad strong-field region. Additionally, this vanishing implies that semiclassical backreaction cannot prevent or significantly affect the classical process of gravitational collapse and horizon formation (as sometimes claimed). This talk is based on the joint work arXiv:2503.00622 with |
| Date: | Wed, 22.04.2026 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Seminar Room A, Waehringer Str. 17, 1090 Wien, 2nd floor |
| Contact: | D. Fajman |
| Cosmology and fundamental physics from compact binary coalescences detected by the LIGO, Virgo and KAGRA collaboration |
| Speaker: | Dr Simone Mastrogiovanni (INFN Rome) |
| Abstract: | The Universe expansion is one of the most puzzling open problems in modern cosmology. For over 20 years, measurements of the Universe expansion rate from close-by and far sources are in tension hinting for the presence of new physics at cosmological scales. Our struggle to corroborate the presence of new physics is due to the difficulty of observing cosmological sources for which the distance is known without the need of a cosmological ladder. However, a new player entered the cosmological match in 2015: Gravitational Waves (GWs) from compact binary coalescences (CBCs). CBCs are Standard Sirens, they are the only known cosmological source for which it is possible to directly measure the luminosity distance from their GW emission. Unfortunately, the GW do not provide the other ingredient to measure the Universe expansion: the redshift. For details see https://indico.global/event/17133/ |
| Date: | Thu, 23.04.2026 |
| Time: | 10:00 |
| Duration: | 60 min |
| Location: | Marietta Blau Institute for Particle Physics, Dominikanerbastei 16 [PSK], 1010 Vienna, Besprechungsraum 3A.1/2 |
| Contact: | Ulyana Dupletsa, Claude Amsler |
| Speaker: | Aephraim Steinberg (University of Toronto) |
| Abstract: | folgt |
| Date: | Fri, 24.04.2026 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | Helmut Rauch Hörsaal ATI |
| Contact: | VCQ Nadine Hilmar |
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