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Calendar of Physics Talks Vienna
| Towards a low energy electron-positron plasma in the lab |
| Speaker: | Dr. Adam Deller (Max Planck Institute for Plasma Physics, Garching, Germany) |
| Abstract: | Positively and negatively charged particles with equal mass can form a pair plasma. For instance, this can occur in extreme astrophysical environments that generate electron-positron pairs at sufficient density for collective effects to occur. The mass symmetry distinguishes pair plasma from the more familiar ion-electron plasma, and many conventional instabilities are expected to be suppressed. The APEX collaboration aims to verify this by creating a low-energy positron-electron plasma in the lab. The experiments will require an unprecedentedly large collection of low-energy positrons. I will present the current status of the APEX project, including the development of ... [complete abstract available here: https://indico.cern.ch/event/1274094/] |
| Date: | Mon, 17.04.2023 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | SMI Seminarraum, Kegelgasse 27, 3. Stock |
| Contact: | Eberhard Widmann, Martin Simon |
| A little piece of quantum de Sitter |
| Speaker: | Eleanor Harris (King's College London) |
| Abstract: | Dilaton gravity models in two dimensions, such as JT gravity, have provided fruitful results as simple holographic models in recent years.
It is possible to deform such theories away from the usual AdS bulk to produce geometries that can be de Sitter-like in the interior.
We will begin with a review of JT gravity, and then will see how by including a timelike Dirichlet boundary, for example, geometries
that interpolate between de Sitter in the IR to anti-de Sitter near the boundary can be found that are stable under thermodynamic fluctuations.
We will conclude by proposing a dual matrix model, whose degrees of freedom will hopefully be able to capture the physics of the de Sitter region in the bulk. |
| Date: | Tue, 18.04.2023 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger Lecture Hall, Faculty of Physics, Boltzmanngasse 5, 5th floor |
| Contact: | D. Grumiller, S. Fredenhagen, E. Battista, R. Ruzziconi |
| --- CANCELLED! (Simplicity, Complexity and the Universe) --- |
| Speaker: | --- CANCELLED! Gian Francesco Giudice (CERN, Genf) --- |
| Date: | Tue, 18.04.2023 |
| Time: | 16:15 |
| Location: | --- CANCELLED! --- |
| Contact: | A. Hoang |
| Black lenses in Kaluza-Klein matter |
| Speaker: | Marcus Khuri (Stony Brook) |
| Abstract: | We present the first examples of formally asymptotically flat black hole solutions with horizons of general lens space topology L(p,q).
These 5-dimensional static/stationary spacetimes are regular on and outside the event horizon for any choice of relatively prime integers 1\leq q |
| Date: | Thu, 20.04.2023 |
| Time: | 15:30 |
| Duration: | 60 min |
| Location: | on zoom https://univienna.zoom.us/j/6540036841?pwd=SytyVkZJZzNyRG9lMm13ejlHeHRRUT09 Meeting ID: 654 003 6841 Passcode: Gs4brS |
| Contact: | P. Chrusciel, D. Fajman |
| Nano-optics with free electrons |
| Speaker: | Mathieu Kociak (CNRS-Paris) |
| Abstract: | Semiconductor quantum dots embedded in photonic nanostructures offer a highly efficient and coherent deterministic photon-emitter interface [1,2]. It constitutes an on-demand single-photon Electron spectroscopy using free electrons in electron microscopes (EM) probably entered the field of nano-optics at the end of the 20th century, with among other the pivotal paper of Yamamoto1 showing the mapping of plasmonic modes with deep sub-wavelength resolution.
Since then, the field has kept growing exponentially, with applications from plasmons, phonons or exciton mapping at near atomic resolution, to quantum optics of nanomaterials or of the free electrons themselves2. These results have been boosted by constant disruptions in technology â monochromation, fs sources of pulsed electrons, high efficiency light injection and detection system in the EM - and theory â introduction of concepts of o |
| Date: | Fri, 21.04.2023 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | ATI Hörsaal/https://tuwien.zoom.us/j/93672218922?pwd=dEZNQ2liVzRNNURvNmVWVE5KUWRiQT09 |
| Contact: | Philipp Haslinger |
| Large Deviations in the Early Universe |
| Speaker: | Timothy Cohen (Oregon University, USA / CERN, Schweiz) |
| Abstract: | Fluctuations play a critical role in cosmology.They are relevant across a range of phenomena from the dynamics of inflation to the formation of structure.In many cases,it is a good approximation to coarse grain these fluctuations(in the sense of a Renormalization Group flow),and they follow a Gaussian distribution as a consequence of the Central Limit Theorem.Yet,some classes of observables are dominated by rare fluctuations and are sensitive to the details of the underlying microphysics.In this talk,I will introduce the Large Deviation Principle,and will explain how it can be used to diagnose when effective approaches fail and one must instead to appeal to the microscopic description.I will illustrate this phenomenon in the context of determining the phase transition to eternal inflation,and will briefly mention applications for the distribution of scalar field fluctuations in de Sitter |
| Date: | Fri, 21.04.2023 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | Fakultaet fuer Physik, Ernst-Mach-HS, Boltzmanngasse 5, 2. Stock |
| Contact: | A. Hoang, J. Pradler, P. Chrusciel |
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