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Calendar of Physics Talks Vienna
| Classical dynamics, arrow of time, and the origin of Heisenberg's commutation relations |
| Speaker: | Detlev Buchholz |
| Abstract: | Based on the assumption that mechanical systems can
be described by Lagrangians and time progresses in a fixed direction,
a dynamical C*-algebra is presented for nonrelativistic particles at
atomic scales. This algebra is based on the concept of operations
and relies exclusively on classical concepts. Nevertheless, it is
inherently non-commutative. Without presupposing any quantization
scheme, the Heisenberg commutation relations for position and velocity
measurements are derived from it. Hilbert space representations of
the algebra lead to the conventional framework of quantum mechanics,
providing a new look on its foundations. (Joint work with
Klaus Fredenhagen.) |
| Date: | Tue, 12.10.2021 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | ESI Lecture Hall |
| Contact: | Romain Ruzziconi, Stefan Fredenhagen |
| Particle design for photocatalytic and photoelectrochemical water splitting |
| Speaker: | Simone Pokrant (Functional Materials, Chemistry and Physics of Materials, Paris-Lodron Universität Salzburg) |
| Abstract: | Almost 50 years after the first demonstration of photocatalytic water splitting by Fujishima and Honda using TiO2 in 1972 [1], the exploitation of photocatalytic and photoelectrochemical water-splitting for solar fuel production is still hindered by an unfavorable device efficiency versus cost ratio [2]. For photocatalytic or photoelectrochemical applications high active surface areas and good charge-transport properties are key features to enhance device performance [3]. Favorable charge transport properties are usually obtained in defect free structures such as single crystals, where the surface area is small in comparison to agglomerates of porous nanoparticles. Nanoparticles, however, suffer from reduced charge extraction and, in the case of photoelectrochemical water splitting, from reduced transport properties to the back electrodes because of multiple grain boundaries. Lately, th |
| Date: | Tue, 12.10.2021 |
| Time: | 16:00 |
| Location: | TU Wien, Institut für Angewandte Physik, E134 1040 Wien, Wiedner Hauptstraße 8-10 Yellow Tower „B“, 5th floor, SEM.R. DB gelb 05 B |
| Contact: | Univ.Prof. Dr. Ulrike Diebold |
| Limits of Jackiw-Teitelboim gravity |
| Speaker: | Daniel Grumiller (Vienna) |
| Abstract: | Some applications require non-Riemannian spacetimes, such as Carrollian or Galilean spacetimes. They describe, respectively, ultra- and non-relativistic limits of gravity.
In my talk I construct the Newton-Cartan version of two-dimensional dilaton gravity, which plays essentially the same role for Newton-Cartan gravity as generic dilaton gravity does for Riemann-Cartan gravity.
LINK: https://arxiv.org/abs/2011.13870 |
| Date: | Thu, 14.10.2021 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | ZOOM: https://univienna.zoom.us/j/6540036841?pwd=SytyVkZJZzNyRG9lMm13ejlHeHRRUT09 |
| Contact: | Piotr Chrusciel, David Fajman |
| A machine learning pipeline for autonomous numerical analytic continuation of Dyson-Schwinger equations |
| Speaker: | Andreas Windisch (Washington University in St. Louis) |
| Abstract: | Dyson-Schwinger equations are a non-perturbative approach to computing n-point functions in quantum field theory. Solving n-point functions in the complex domain gives insights into physical properties of the propagating degree of freedom, such as mass and multi-particle thresholds, and can also shed light on the exclusion of the particle in question from the space of asymptotic states. Considering the quark propagator Dyson-Schwinger equation in Landau gauge in the complex domain, one has to deform the integration contour in the complex plane of the loop momentum of the self energy diagram. Here we propose a machine learning based pipeline that addresses all main issues to constitute a fully autonomous system that produces suitable integration contours for every iteration step using Deep Reinforcement Learning. |
| Date: | Thu, 14.10.2021 |
| Time: | 16:30 |
| Duration: | 60 min |
| Location: | https://tuwien.zoom.us/j/95482849369?pwd=SkU2WU5hMVJBQWsyVlFXRlRvQlIvdz09 |
| Contact: | Laura Donnay, Andreas Ipp |
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