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Calendar of Physics Talks Vienna
| What is really tested in gravitationally mediated entanglement experiments? |
| Speaker: | Helmut Rumpf (University of Vienna) |
| Abstract: | Recently it was proposed that GME experiments may probe linearized gravity only as a quantum controlled field and not as a quantum field theory. I will argue that the concept of a relativistic quantum controlled field is fundamentally flawed because of causality violation.
Quantum control is also implicit in a recent path-integral description of those experiments, which casts doubt on its validity beyond the Newtonian approximation. |
| Date: | Tue, 01.04.2025 |
| Time: | 13:00 |
| Duration: | 60 min |
| Location: | Seminar Room A, Waehringer Str. 17, 1090 Wien, 2nd floor |
| Contact: | P.C. Aichelburg |
| B-branes in hybrids and GLSMs |
| Speaker: | Johanna Knapp (University of Melbourne) |
| Abstract: | We consider type II string theory on Calabi-Yau threefolds with B-type D-branes. Hybrid models appear in limiting regions of the stringy Kahler moduli space of the Calabi-Yau. They are Landau-Ginzburg models fibred over a compact base manifold. We give a physics derivation of B-type D-branes in hybrids and show that they are matrix factorisations of the hybrid superpotential, combined with geometric data associated to the base. Lifting these branes to the gauged linear sigma model (GLSM) and making use of the GLSM hemisphere partition function, we establish a connection between geometric and hybrid branes. As an application, we discuss a hybrid model that shares the moduli space with a well-known two-parameter Calabi-Yau hypersurface. This is joint work with Robert Pryor. |
| Date: | Tue, 01.04.2025 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-HS, Boltzmanngasse 5, 1090 Wien, 5.Stock |
| Contact: | S. Fredenhagen, M. Sperling |
| 3D Localisation Microscopy and Single Molecule Tracking of DNA Nanostructures and Cell Membrane Proteins Using Defocused Imaging |
| Speaker: | Anna Gaugutz (TU Wien, IAP, FB Biophysik) |
| Abstract: | At the interface of interacting cells, the 3D topography of the plasma membranes influences biomolecular interactions, for example by sterically hindering the diffusion of membrane proteins. A prominent example is the exclusion of the phosphatase CD45 with its large extracellular domain from the close contact zone during T cell activation . To investigate these exclusion effects, it is essential to track individual membrane proteins in 3D. While standard single molecule localisation microscopy (SMLM) offers high localisation precision in lateral dimensions, its performance in the axial z-direction is limited. Here we describe a new version of SMLM based on defocused imaging which allows tracking of single proteins in 3D and achieves a resolution of 10 nm along the axial direction. The method is validated by tracking two DNA nanoprobes (DNA-NPs) on supported lipid bilayers. DNA-NPs are cu |
| Date: | Tue, 01.04.2025 |
| 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: | Univ.Prof. Gerhard Schütz |
| New Results from the CMS Experiment and the HEPHY CMS Group |
| Speaker: | Robert Schoefbeck (HEPHY, OEAW Vienna) |
| Abstract: | Over the past year, the CMS experiment has produced a series of results, concluding long-standing experimental quests, achieving unprecedented precision, and challenging established lore in several areas. In this talk, I will highlight recent key measurements in the Higgs and top-quark sectors, emphasizing the crucial and ongoing interplay between theoretical insights and experimental techniques.
Furthermore, I will outline emerging projects at HEPHY and discuss how cutting-edge theoretical and computational approaches will sharpen the toolkit for continued exploration of nature at the shortest scales.
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| Date: | Tue, 01.04.2025 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-HS, Boltzmanngasse 5, 1090 Wien, 5.Stock |
| Contact: | A. Hoang, M. Procura |
| Two linear instabilities in general relativity |
| Speaker: | Sam Collingbourne & Jan Sbierski (University of Edinburgh) |
| Abstract: | The first half concerns GregoryâLaflamme (GL) instabilities which occur at the level of linearised gravity. Heuristic and numerical evidence suggests that GL instabilities plague black holes in dimensions greater than 4 which have an event horizon that has one direction that is large compared to all others. Sam will discuss a direct mathematical proof of the GregoryâLaflamme instability for the 5D Schwarzschild black string. The proof relies upon reducing the linearised vacuum Einstein equation to a Schrödinger equation to which direct variational methods can be applied.
The second half of the talk concerns the blue-shift instability in the interior of rotating Kerr black holes at the level of linearized gravity. This instability is intimately connected to Penroseâs strong cosmic censorship conjecture. In contrast to the GL instability, this instability is weak in the sense that the C^0 |
| Date: | Wed, 02.04.2025 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Seminar Room A, Waehringer Str. 17, 1090 Wien, 2nd floor |
| Contact: | D. Fajman |
| Speaker: | Angelika Wiegele (University of Klagenfurt) |
| Abstract: | folgt |
| Date: | Fri, 04.04.2025 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | Helmut Rauch Hörsaal ATI |
| Contact: | Paul Erker |
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