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Calendar of Physics Talks Vienna
| Optical harmonic generation from squeezed vacuum |
| Speaker: | Maria Chekhova (Max-Planck Institute for the Science of Light, Erlangen, Germany) |
| Abstract: | Squeezed vacuum, a state of light at the output of an unseeded optical parametric amplifier, manifests many interesting quantum features such as quadrature squeezing and photon-number correlations, up to the violation of certain Bell’s inequalities. When its brightness (number of photons per mode) is high, it becomes highly promising for light-matter interactions. In our recent experiments we used it as a pump for the generation of optical harmonics of orders 2-4 on the surfaces of different materials. We show that due to its increased photon-number fluctuations, bright squeezed vacuum is much more efficient for multi-photon effects than coherent and even thermal light. For instance, in the case of the fourth-harmonic generation and other four-photon effects, the efficiency exceeds that of coherent light by more than two orders of magnitude. This offers a possibility of using bright sque |
| Date: | Mon, 30.05.2016 |
| Time: | 17:30 |
| Duration: | 60 min |
| Location: | HS 7, Schütte-Lihotzky, Karlsplatz 13, Vienna |
| Contact: | www.coqus.at / Christina Becker |
| The IKKT model and its relation to D=10 super-Yang-Mills and stringtheorie |
| Speaker: | Timon Salar Gutleb (University of Vienna) |
| Abstract: | Im Rahmen des Seminars für Mathematische Physik: The intention of this talk is to give an introduction to the IKKT matrix model and its connection to SYM gauge theories as well as String Theory. Our main focus will be deriving the IKKT action from the Nambu–Goto action for the string, thus highlighting the relationship between the IKKT matrix model and String Theory. This derivation
will contain and explain various canonical methods like Polyakov’s trick.
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| Date: | Tue, 31.05.2016 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Kleiner Seminarraum der Theor. Physik, 5. Stock Boltzmanngasse 5 |
| Contact: | H. Steinacker |
| Surface Reactivity and Homoepitaxial Growth of SrTiO3(110) |
| Speaker: | Dipl.-Ing. Stefan Gerhold (TU Wien, Insitut für Angewandte Physik, AG Oberflächenphysik) |
| Abstract: | Strontium titanate (SrTiO3 or STO) has evolved as a prototype for the class of perovskite oxides. It shows a high photocatalytic efficiency for water-splitting, and it is commonly used as a substrate for the growth of complex oxides. The STO (110) surface has been investigated with surface sensitive experimental techniques. The surface forms a variety of reconstructions, which are related to the near-surface stoichiometry. We have investigated the adsorption of water on the (4x1) reconstructed surface and have modified its reactivity by adsorption of NiO clusters. Recently we have extended our surface science chamber with a pulsed laser deposition (PLD) setup with in-situ transfer of as-grown samples. By utilizing reflection high-energy electron reflection (RHEED) during growth, we obtain exquisite control over the film thickness. Our approach of combining the high-pressure PLD growth wi |
| Date: | Tue, 31.05.2016 |
| Time: | 16:00 |
| Location: | Technische Universität Wien, Institut für Angewandte Physik, E134 yellow tower „B“, 5th floor, Sem.R. DB gelb 05 B (room number DB05L03) 1040 Wien, Wiedner Hauptstraße 8-10 |
| Contact: | Univ.Prof. Dr. Ulrike Diebold |
| Studies of discrete symmetries and quantum entanglement using Jagiellonian Positron Emission Tomograph |
| Speaker: | Pawel Moskal (Univ. Krakau) |
| Abstract: | im Rahmen des Teilchenphysikseminars |
| Date: | Tue, 31.05.2016 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | A. Hoang, B. Hiesmayr |
| Particle detectors for hadron physics and applications |
| Speaker: | Prof. Kai Brinkmann (Justus-Liebig Universität Giessen) |
| Abstract: | Modern experiments in particle and nuclear physics often rely on detection equipment that is custom designed for optimum performance within a given physics scope. Designed components include everything from detector materials to readout electronics. While many components are commercially available, careful assessment of the physics is required to identify hardware parts where R&D efforts potentially pay off most in the overall detector performance with respect to the key physics features of an experiment. Examples for a number of detector setups will be presented where R&D efforts are ongoing or have been applied to upgrades of existing detector arrays in order to meet modern standards for readout, radiation hardness etc... This involves both charged particle tracking as well as electromagnetic calorimetry, e.g. ... [full abstract: https://indico.smi.oeaw.ac.at/event/174/] |
| Date: | Wed, 01.06.2016 |
| Time: | 17:00 |
| Duration: | 60 min |
| Location: | Stefan-Meyer-Institut, Boltzmanngasse 3, 1090 Wien, Seminarraum 3-2-08 (2. Stock) |
| Contact: | Prof. Dr. Eberhard Widmann, Dr. Martin Simon |
| Speaker: | Arkadij Bojko (Uni Wien) |
| Abstract: | Im Rahmen des Literaturseminars: The Lagrange densities for metrics give Euler-Lagrange expressions which transform as tensor densities and are symmetric and divergence-free. This, together with requiring the tensor density to depend on only up to the second derivative of the metric, allowed Lovelock to find a general dimension-dependent form of such tensorial quantities. I will go through the derivation of his results in this matter. At the end I will also show that for any such divergence-free, symmetric tensor density there exists an associated L-degenerate Lagrange density. |
| Date: | Thu, 02.06.2016 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Arbeitsgruppe Gravitation, Währinger Strasse 17, Seminarraum A, 2. Stock, 1090 Wien |
| Contact: | H. Rumpf |
| What is truly quantum about quantum thermodynamics? |
| Speaker: | Gershon Kurizki (Weizmann Institute of Science, Israel) |
| Abstract: | Synopsis: I will argue that quantum mechanics endows us with resources that may boost thermodynamic performance: heat-machine power, cooling speed or work, but the basic thermodynamic bounds are still adhered to.
The debated rapport between thermodynamics and quantum mechanics will be addressed in the framework of the theory of periodically driven/controlled quantum thermodynamic machines. The basic models studied by us are a two-level system (TLS) or a harmonic oscillator, whose energy is periodically modulated while the system is coupled to two distinct thermal baths. When the modulation interval is short compared to the bath memory time, the system–bath correlations are affected, thereby causing cooling or heating of the TLS, depending on the interval. This setup constitutes the simplest (minimal) quantum heat machine (QHM) that may operate as either an engine or a refrigerator, depending on the modulation/driving rate. It is used by us to scrutinize basic thermodynamic principles in the quantum domain:
(i) Only driven/modulated QHMs that do not involve coherence may attain the Carnot efficiency bound and maximum power, whereas coherently-driven QHM suffer from inadequate performance. It is possible to surpass the Carnot bound when the driving is done by a quantum device (piston) in an appropriate state. However, such enhanced efficiency does not mean that quantum effects invalidate the Carnot bound: their classical analog is a non-thermal bath whose temperature is controlled by its state.
(ii) An extension of this model to multiple entangled systems shows that the power output can be boosted by the quantum cooperativity of these systems, but again this effect has a classical analog.
(iii) The refrigeration effected by such QHMs persists as the temperature approaches absolute zero for certain quantized baths, e.g., magnons, thus challenging the Third Law (Nernst's unattainability principle).
(iv) System–bath correlations allow more work extraction under ultrafast modulation than currently expected from the Szilard–Landauer principle.
Thus, we may conclude that heat machines in the quantum domain may benefit from hitherto unexploited quantum resources, but they still comply with traditional thermodynamic rules.
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| Date: | Fri, 03.06.2016 |
| Time: | 15:30 |
| Location: | Atominstitut, Hörsaal, Stadionallee 2, Wien 2 |
| Contact: | J. Schmiedmayer - I. Mazets |
| Introduction to Collider Physics and Effective Theory Methods |
| Speaker: | Prof. Iain Stewart (Massachusetts Institute of Technology) |
| Abstract: | zur 1. Vorlesung im Rahmen der Schrödinger-Gastprofessur 2016:
In these lectures I introduce the key conceptual ingredients needed to understand and make predictions for processes like Higgs production at the Large Hadron Collider. This includes
the concepts of factorization, running couplings, parton distributions, and jets.
I will also discuss how the tools of effective field theory can be used to simplify calculations
for colliders, by exploiting universal features of soft and collinear radiation.
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| Date: | Fri, 03.06.2016 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | A. Hoang, H. Neufeld, A. Rebhan |
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