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Calendar of Physics Talks Vienna
| Strongly-interacting bosons at 2D-1D dimensional crossover |
| Speaker: | Hepeng Yao (University of Geneva) |
| Abstract: | Quantum gases at dimensional crossover exhibit fruitful physics which reflects
fascinating properties of non-integer dimensions. While various fascinating
researches have been carried out in the tight-binding limit [1-3], the smooth
dimensional crossover for strongly-interacting bosons in continuous lattice, which
is beyond mean-field theory and strongly adapted to current generation of
experiments, is rarely studied. In this talk, I will first give a brief introduction to
the correlation properties of bosons at low integer dimensions. Then, I will present
our study about strongly-interacting bosons under continuous potential at 2D-1D
dimensional crossover [4]. Using quantum Monte Carlo calculations, we
investigate this dimensional crossover by computing longitudinal and transverse
superfluid fractions as well as the superfluid correlation as a function of
temperature, interac |
| Date: | Mon, 17.10.2022 |
| Time: | 14:00 |
| Duration: | 45 min |
| Location: | Seminarraum ATI |
| Contact: | Jörg Schmiedmayer |
| Flat Space Holography in 3D |
| Speaker: | Max Riegler (TU Wien) |
| Abstract: | The holographic principle provides a very powerful relation between quantum field theories and theories of quantum gravity.
While its most famous avatar, the anti-de Sitter/conformal field theory (AdS/CFT) correspondence, has been extensively studied during the past 25 years,
extensions of holography to quantum gravity in de-Sitter or flat space are still under active development. In this talk, I will introduce the main ideas and
concepts used to establish holography for asymptotically flat spacetimes in three spacetime dimensions.
A particular focus will be on the basic concepts of the dual Bondi-Metzner-van der Burg-Sachs invariant quantum field theories (possibly with additional u(1) charges)
and how to set up a holographic dictionary involving these quantum field theories and asymptotically flat spacetimes.
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| Date: | Tue, 18.10.2022 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Erwin-Schrödinger-Hörsaal, University of Vienna, Boltzmanngasse 5, 5th floor, Room Nr. 3500 |
| Contact: | S. Fredenhagen, D. Grumiller, E. Battista, R. Ruzziconi |
| Applications of Machine Learning in Surface Science: Between Structure Search and Automated Experiments |
| Speaker: | Oliver Hofmann (Technische Universität Graz, Institute of Solid State Physics) |
| Abstract: | The advent of so-called self-learning algorithms allows to both generate and analyze large amounts of computational or experimental data with unprecedented accuracy and speed. In the past years, this allowed us to study systems and problems in surface science that were hitherto intractable. In this work, I will give a brief introduction into the basic concepts of machine learning and then present three different applications that we pursue in my group.
The first and major part presents a method to determine the structure of inorganic/organic interfaces from first principles. With the ability to predict which structures form under which conditions, it is possible to (re)evaluate seminal experimental results. This allows us to directly extract relevant physics that govern charge-transfer at the interface. Furthermore, not only is it possible to predict which structures form under certain |
| Date: | Tue, 18.10.2022 |
| 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. PhD Gareth Parkinson |
| QED at NNLO and beyond for precision experiments |
| Speaker: | Yannick Ulrich (Durham University) |
| Abstract: | Low-energy experiments allow for some of the most precise measurements in particle physics, such as g-2.
To make the most of these experiments, theory needs to match the experimental precision.
Over the last decade, this meant that even in QED next-to-next-to-leading order calculations (or even more in some cases) became necessary.
I will discuss some of the challenges faced when dealing with QED corrections and discuss some possible solutions that we have implemented
in McMule (Monte Carlo for MUons and other LEptons). McMule is a framework that we have developed to obtain NNLO predictions for a number
of processes, such as $e\mu \to e\mu$, $ee \to ee$ and $\mu \to e\nu\bar\nu$. |
| Date: | Tue, 18.10.2022 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Erwin-Schrödinger-HS, Fakultät für Physik, Boltzmanngasse 5, 5. Stock sowie ZOOM https://univienna.zoom.us/j/93427906843?pwd=YjhSejdUVW16QjVQYUh5TVNSNFNhQT09 |
| Contact: | A. Hoang, M. Procura, A. Broggio |
| Black holes and ultra-compact objects in Einstein-scalar-Gauss-Bonnet theories |
| Speaker: | Jutta Kunz (Universität Oldenburg) |
| Abstract: | Einstein-scalar-Gauss-Bonnet theories lead to second order field equations, that feature a wide variety of interesting compact solutions.
Depending on the coupling function of the scalar field to the Gauss-Bonnet term, different types of solutions are obtained.
In this talk I will focus on coupling functions, that allow the black hole solutions of General Relativity to remain solutions of the field equations,
but that yield in addition scalarized solutions. Besides a variety of scalarized black hole solutions I will discuss also other types of compact solutions.
These may feature light rings and echoes and quality as UCOs, ultra-compact objects. |
| Date: | Thu, 20.10.2022 |
| Time: | 15:15 |
| Duration: | 60 min |
| Location: | via ZOOM https://univienna.zoom.us/j/6540036841?pwd=SytyVkZJZzNyRG9lMm13ejlHeHRRUT09 |
| Contact: | P. Chrusciel, D. Fajman |
| Hydrodynamic Attractors into the Unknown |
| Speaker: | Michal P. Heller (Ghent University) |
| Abstract: | Dynamical attractors offer a new perspective on thermalization processes in nuclear collisions at RHIC and LHC. In particular, the success of relativistic hydrodynamics in modeling far from equilibrium states has been attributed to the presence of hydrodynamic attractors. As interesting as it sounds, it is not known how general this finding is: till recently there existed simply no methods to study hydrodynamic attractors beyond the idealized setting of the boost-invariant dynamics without transverse expansion. In the talk, I will discuss ideas going in the direction of general hydrodynamic attractors and present what is new they reveal about the known cases. Based on 2003.07368, 2203.16549 and 2110.07621, 2112.12794. |
| Date: | Thu, 20.10.2022 |
| Time: | 16:30 |
| Duration: | 60 min |
| Location: | Freihaus, Sem.R. DB gelb 10 |
| Contact: | Kirill Boguslavski, Anton Rebhan, Iva Lovrekovic |
| Continuous Bose-Einstein condensation and superradiant clocks |
| Speaker: | Florian Schreck (University of Amsterdam) |
| Abstract: | Ultracold quantum gases are excellent platforms for quantum simulation and sensing. So far these gases have been produced using time-sequential cooling stages and after creation they unfortunately decay through unavoidable loss processes. This limits what can be done with them. For example it becomes impossible to extract a continuous-wave atom laser, which has promising applications for precision measurement through atom interferometry [1]. I will present how we achieve continuous Bose-Einstein condensation and create condensates (BECs) that persist in a steady-state for as long as we desire. Atom loss is compensated by feeding fresh atoms from a continuously replenished thermal source into the BEC by Bose-stimulated gain [2]. Our experiment is the matter wave analog of a cw optical laser with fully reflective cavity mirrors. The only step missing to create a continuous-wave atom laser |
| Date: | Fri, 21.10.2022 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | ATI Hörsaal/https://tuwien.zoom.us/j/93672218922?pwd=dEZNQ2liVzRNNURvNmVWVE5KUWRiQT09 |
| Contact: | Jörg Schmiedmayer |
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