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Calendar of Physics Talks Vienna
| Twisted eleven-dimensional supergravity and exceptional Lie algebras |
| Speaker: | Ingmar Saberi (LMU) |
| Abstract: | In recent years, there has been a great deal of progress on ideas related to twisted supergravity,
building on the definition given by Costello and Li. Much of what is explicitly known about these theories
comes from the topological B-model, whose string field theory conjecturally produces the holomorphic twist of type IIB supergravity.
Progress on eleven-dimensional supergravity has been hindered, in part, by the lack of such a worldsheet approach.
I will discuss a rigorous computation of the twist of the free eleven-dimensional supergravity multiplet,
as well as an interacting BV theory with this field content that passes a large number of consistency checks.
Surprisingly, the resulting holomorphic theory on flat space is closely related to the infinite-dimensional
exceptional simple Lie superalgebra E(5,10). This is joint work with Surya Raghavendran and Brian Williams. |
| Date: | Tue, 21.06.2022 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Zoom https://univienna.zoom.us/j/64871597658?pwd=eDdWUEIwd0l5Z211RkovWVZhdE9xUT09 ID meeting: 648 7159 7658 Passcode: 641201 |
| Contact: | S. Fredenhagen, D. Grumiller, E. Battista, R. Ruzziconi |
| Comparison of protein interaction using membrane model systems and single-molecule measurements |
| Speaker: | Ulrich Ramach (TU Wien, Institut für Angewandte Physik) |
| Abstract: | Protein-protein interactions regulate cell communication and are therefore important for our immune system. One protein of interest is the CD4 protein, which is a glycoprotein that serves as a co-receptor for the T-cell receptor (TCR) and can be found on different immune cells. Direct interaction between cells expressing CD4 and cells expressing its counterpart, the major histocompatibility complex class II (MHC II) is reported to be low due to its assisting role in the TCR-MHC II interaction. This interaction is happening in the vicinity of hundreds of different surface proteins as well as glycocalyx proteins like CD45, posing a challenge for accurately mimicking the protein interaction on model membranes.
This work gives an overview of choosing a model membrane system as well as protein-protein interaction using model membranes in SFA and single-molecule AFM.
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| Date: | Tue, 21.06.2022 |
| 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. Dr. M. Valtiner |
| Electrochemical manipulation of catechol reaction mechanisms |
| Speaker: | Julia Appenroth (TU Wien, Institut für Angewandte Physik) |
| Abstract: | Redox-active catechols, in particular L-DOPA and dopamine, are found in many adhesive biological systems. For example, in marine mussels L-DOPA containing byssus threads are shown to adhere to different substrates in harsh saline environments. Their oxidation and reduction can be driven both by pH changes and electrochemistry. While various models have been proposed, the exact reaction paths of these catechols remain a topic of discussion. To gain more insight into the dynamics and redox activity of catechols in aqueous solution their reaction paths and products were studied using electrochemistry and UV-vis. We further used this knowledge to develop a polymeric hydrogel that was electro-crosslinked and showed high adhesion compared to mussel foot proteins at the polymer/water interface.
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| Date: | Tue, 21.06.2022 |
| 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. Dr.M. Valtiner |
| EFT effects in VBS: lessons from UV complete models |
| Speaker: | Dieter Zeppenfeld (KIT) |
| Abstract: | Vector boson scattering (VBS), with its intricate cancellation between Higgs and electroweak boson exchanges,
has in recent years advanced from theoretical consideration to experimental investigation at the LHC.
Via its sensitivity to quartic gauge couplings, it has opened new roads to BSM searches.
The talk will first consider such BSM effects in an effective field theory (EFT) language, including the unitarity problems of a truncated EFT,
as a bottom-up approach. This will be contrasted to a top-down approach, within a large class of UV-complete, i.e. renormalizable models
of BSM physics. The top-down approach allows to quantify the validity range of the EFT, it sheds light on unitarization procedures,
but above all it suggests improved strategies for BSM searches in VBS. |
| Date: | Tue, 21.06.2022 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-Hoersaal, Fakultaet für Physik, Boltzmanngasse 5, 5. Stock ZOOM https://univienna.zoom.us/j/93427906843?pwd=YjhSejdUVW16QjVQYUh5TVNSNFNhQT09 Meeti |
| Contact: | A. Hoang, M. Procura |
| Double Null Data and the Characteristic Problem in General Relativity |
| Speaker: | Gabriel Sanchez-Perez (University of Salamanca) |
| Abstract: | General Relativity admits a well-posed characteristic initial value problem, where data is given on two transverse, null hypersurfaces.
In this seminar, a new approach in which the initial data is defined abstractly and in a fully diffeomorphism and gauge-covariant way is presented. In order to achieve this we employ the so-called hypersurface data formalism, a framework in which one can study general hypersurfaces of any causal character from an abstract point of view (i.e. independent of any spacetime notion). Our abstract geometrization puts the characteristic problem on a similar footing as the standard Cauchy problem in General Relativity, in the sense that the initial data has been completely detached from the spacetime one wishes to construct.
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| Date: | Wed, 22.06.2022 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | Seminarraum A, Gravitationsphysik, Waehringer Strasse 17, 2. Stock ZOOM https://univienna.zoom.us/j/6540036841?pwd=SytyVkZJZzNyRG9lMm13ejlHeHRRUT09 |
| Contact: | P. Chrusciel, D. Fajman |
| Positronium precision spectroscopy: Measurement of the 1S-2S and excited state fine and hyperfine transitions |
| Speaker: | Michael W. Heiss (ETH Zuerich) |
| Abstract: | Starts at 16h !!
Positronium is an excellent system to test bound state QED theory to very high precision, since it is almost exclusively governed by the electro-magnetic force and does not exhibit finite size effects. Numerous precise experiments have therefore been conducted in the past to measure multiple transitions this system. However, some experiments show disagreements of more than 4σ with most recent calculations. Furthermore, new precision measurements of the 1S-2S and excited state fine and hyperfine splitting would not only allow for stringent tests of QED theory to current theoretical precision, but also to test CPT invariance complementary to measurements in hydrogen. This talk will report on past results obtained at ETH Zurich measuring the 1S-2S transition and current efforts to measure the fine and hyperfine splitting in Positronium.
[indico.cern.ch/event/1170062/] |
| Date: | Wed, 22.06.2022 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | SMI Seminarraum, Kegelgasse 27, 3. Stock (online participation possible: request zoom link before 12:00 of June 22nd via email martin.simon at oeaw.ac.at) |
| Contact: | Eberhard Widmann, Martin Simon |
| Interferometric Unruh Detectors for Bose-Einstein Condensates |
| Speaker: | Sebastian Erne, TU Wien |
| Abstract: | Ultracold atoms and their non-equilibrium evolution present an ideal platform to study fundamental processes of quantum field theory and the relaxation dynamics of quantum many-body systems.
Here, I will present recent results and future prospects for analogue quantum simulators based on effective field theory descriptions.
In particular, I will discuss the measurement of the analogue circular Unruh effect via local interferometric two-frequency detectors [1,2].
The continuous non-destructive measurements of cold atom systems paves the way to study this fundamental and yet still untested prediction of quantum field theory,
that a linearly accelerated observer in the vacuum observes a thermal state at the Unruh-temperature. |
| Date: | Thu, 23.06.2022 |
| Time: | 15:00 |
| Duration: | 60 min |
| Location: | Gravitationsphysik, Seminarraum A, Waehringerstrasse 17, 2nd floor |
| Contact: | P. Chrusciel, D. Fajman |
| IMBM Seminar: "Physics @ Null Boundaries, Edition 2022" |
| Speaker: | Shahin Sheikh Jabbari (Institute for Research in Fundamental Sciences (IPM)) |
| Abstract: | To formulate gravity in spacetimes bounded by an arbitrary hypothetical null boundary, boundary degrees of freedom (d.o.f) should be added to account for the d.o.f and dynamics in the spacetime regions excised behind the boundary. In D dimensional case, null boundary d.o.f are labelled by D charges defined at D-2 dimensional spacelike slices of the null boundary. While boundary modes can have their own boundary dynamics, their interaction with the bulk modes is governed by flux-balance equations which may be interpreted as diffusion equations describing dissolution of bulk gravitons into the boundary. From boundary viewpoint, boundary d.o.f obey local thermodynamical equations at the boundary. Our description suggests a new semiclassical quantization where boundary d.o.f are quantized while bulk is classical. This semiclassical treatment may be relevant to questions in black hole physics |
| Date: | Thu, 23.06.2022 |
| Time: | 16:30 |
| Duration: | 60 min |
| Location: | TU Wien, Freihaus, Seminar room on 9th floor |
| Contact: | Daniel Grumiller, Iva Lovrekovic |
| Quantum detectors for (low and high energy) particle physics |
| Speaker: | Michael Doser (CERN) |
| Abstract: | After a short introduction into the involvement of different existing families of detectors relying on quantum effects and relevant to the field of (mostly low energy) particle physics, a small number of possible ideas for applications in the context of high energy particle physics (calorimetry, particle ID, tracking) will be presented and discussed. A particular emphasis will be placed on the R&D required to transform these more speculative ideas into proof-of-principle prototype devices.
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| Date: | Fri, 24.06.2022 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | ATI Hörsaal/https://tuwien.zoom.us/j/93672218922?pwd=dEZNQ2liVzRNNURvNmVWVE5KUWRiQT09 |
| Contact: | Jochen Schieck |
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