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Calendar of Physics Talks Vienna
| Metric reconstruction for non-radiative spacetimes |
| Speaker: | Roberto Oliveri (LUTH, Paris Meudon) |
| Abstract: | Multipole moments are important quantities to characterize spacetimes. In General Relativity, the most general vacuum solution with no incoming radiation is parametrized by two sets of infinite multipole moments. In this talk, we focus on non-radiative spacetimes and provide a characterization thereof in terms of a tower of multipole moments. This tower encodes non-radiative and non-stationary features of the gravitational field at null infinity, and generalizes the Geroch-Hansen moments for stationary spacetimes. Moreover, such a tower of moments is identified with charges associated to the ð¿ð¤1+â algebra recently discovered in the structure of asymptotically flat spacetimes. |
| Date: | Tue, 28.06.2022 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Sem.R. DA, gruen 05 (TU Wien, Freihaus, Wiedner Hauptstrasse ) 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 |
| Metals Oxides as Model Supports for Single Atom Catalysis |
| Speaker: | Lena Haager (TU Wien, Institut für Angewandte Physik) |
| Abstract: | Single-atom catalysis (SAC) offers an opportunity to minimize the amount of precious catalyst material required for traditional heterogeneous catalysis and to âheterogenizeâ reactions presently requiring homogeneous catalysis; this would eliminate the problem of separating catalyst and product, while retaining the excellent selectivity and activity of homogeneous catalysts.
Unravelling how metal atoms bind to metal oxide supports is crucial for a better understanding of the SAC´s catalytic properties. Using STM, nc-AFM and XPS, we compare several transition metals on different metal oxide support surfaces such as Fe2O3(11 Ì
02), rutile TiO2(110) and anatase TiO2(101) and the influence of water on the dispersion of these systems.
This study points out the importance of metal-support interaction and the surprisingly different behaviour of the transition metals on different metal oxide supp |
| Date: | Tue, 28.06.2022 |
| 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. Ulrike Diebold |
| Surface Structures of La0.8Sr0.2MnO3 (001) Thin Films |
| Speaker: | Erik Rheinfrank (TU Wien, Institut für Angewandte Physik) |
| Abstract: | Lanthanum-strontium manganite (La0.8Sr0.2MnO3, LSMO) is a perovskite oxide used as a cathode material in solid oxide fuel cells. To gain deeper insights into the reaction mechanisms, it is important to understand the structure of the surface at the atomic scale. To this end, atomically flat single-crystalline LSMO thin films were grown on Nb-doped SrTiO3 (001) substrates via pulsed laser deposition (PLD). The as-grown films were transferred in UHV from the PLD chamber to a surface science system. Studying the LSMO (001) surface by STM and LEED unveils various and unusual (cubic quasi-periodic) surface structures. They depend on the oxygen chemical potential upon annealing and termination of the surface (Mn or La/Sr). |
| Date: | Tue, 28.06.2022 |
| 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. Ulrike Diebold |
| Quantum Fokker-Planck master equation for continuous feedback control and its applications |
| Speaker: | Faraj Bakhshinezhad (Lund University) |
| Abstract: | Measurement and feedback control are essential features of quantum science, with applications ranging from quantum technology protocols to information-to-work conversion in quantum thermo- dynamics. Theoretical descriptions of feedback control are typically given in terms of stochastic equations requiring numerical solutions, or are limited to linear feedback protocols. In this talk, we present a formalism for continuous quantum measurement and feedback, both linear and nonlinear. Our main result is a quantum Fokker-Planck master equation describing the joint dynamics of a quantum system and a detector with finite bandwidth. For fast measurements, we derive a Markovian master equation for the system alone, amenable to analytical treatment. We illustrate our formalism by investigating two basic information engines, one quantum and one classical. We also apply our formalism to a continuous |
| Date: | Wed, 29.06.2022 |
| Time: | 14:00 |
| Duration: | 45 min |
| Location: | Seminarraum Neubau ZE01-1 |
| Contact: | Marcus Huber |
| IMBM Seminar: Generalized Clausius inequality, error tolerant memory and the quantum null energy condition |
| Speaker: | Ayan Mukhopadhyay (Indian Institute of Technology, Madras) |
| Abstract: | Quantum thermodynamics generalizes Clausius inequality stating that the irreversible entropy production is not only positive, but also has both a lower and an upper bound for a given physical process. We show that the study of the quantum null energy condition in holographic quenches gives explicit upper and lower bounds for the irreversible entropy production and also entanglement growth in two dimensional systems. We also apply these methods to obtain a refined version of Landauer principle, in which we compute the minimum irreversible entropy production needed to delete encoded quantum information, and obtain analytic results for a large number of encoding qubits. We find that, for certain forms of encoding, fast deletion is impossible if the encoded bits are squeezed over a sufficiently small length scale. This circumvents no-go theorems based on stabilizer codes. |
| Date: | Thu, 30.06.2022 |
| Time: | 16:30 |
| Duration: | 60 min |
| Location: | TU Wien, Freihaus, Sem.R. DB gelb 09 |
| Contact: | Iva Lovrekovic |
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