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Calendar of Physics Talks Vienna
| Inflationary quasiparticle creation and thermalisation dynamics in a Bose-Josephson junction |
| Speaker: | Anna Posazhennikova (Royal Holloway University of London) |
| Abstract: | A Bose-Josephson junction is an example of an isolated, nonequilibrium many-body quantum system. In spite of the isolation effective thermalizaiton of such a system is generically observed. We propose a mechanism which may lead to such a thermalisation.
The main idea is that in nonequilibrium quasi-particles get inevitably excited to higher levels of the double-well trap and should be taken into account.
We describe such excitations fully quantum-mechanically while restricting the description of the condensates to semi-classical. We find that indeed thermalisation is possible in such a system, because the quasiparticle cloud serves as heat reservoir for the condensates.
We also find several interesting time scales which govern the nonequilibrium dynamics. One of them, for example, characterises the effective quasiparticle decoupling from condensates at long times.
I will discuss the n |
| Date: | Mon, 18.07.2016 |
| Time: | 11:00 |
| Duration: | 90 min |
| Location: | Atominstitut, seminar room Stadionallee 2, 1020 Wien |
| Contact: | Jörg Schmiedmayer |
| The unit interval, Bernoulli numbers, and the Magnus expansion |
| Speaker: | Dr. Florian Schätz (U Luxembourg) |
| Abstract: | The aim of the talk is to explain a link between the three objects mentioned in the title, i.e. the unit interval, Bernoulli numbers, and the Magnus expansion. This link emerges when one ponders the rational homotopy theory of 1-dim simplicial complexes, or - equivalently, but physically speaking - from the computation of an effective action functional in 1-dim BF-theory. Part of the talk relies on joint work with Ruggero Bandiera.
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| Date: | Tue, 19.07.2016 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Erwin Schrödinger International Institute, Boltzmanngasse 9, 1090 Wien, Boltzmann lecture hall |
| Contact: | secr@esi.ac.at |
| Ion Beam Analysis in a Helium Ion Microscope |
| Speaker: | Dr. René Heller (Helmholtz-Zentrum Dresden-Rossendorf, Dresden/Germany) |
| Abstract: | Helium Ion Microscopy (HIM) has developed into a frequently used imaging technique within recent years. Using (30keV) He ions provides several advantages over scanning electron microscopy (SEM) such as, a reduced interaction volume, a better imaging resolution as well as a highest field of depth.
Image generation in a HIM is based on evaluating the number of emitted secondary electrons (SE) delivering an excellent topographic contrast. Information on the surface chemistry is barely provided by the SEs. However, the back-scattered He ions carry that information but they are not analyzed in a HIM by default.
This talk will focus on the implementation of Time-of-Flight Back-scattering Spectrometry (ToF-BS) in a HIM as done at the HZDRs Ion Beam Center recently. ToF-BS enables local element analysis with a lateral resolution on the nm scale. In combination with the excellent imaging capabili |
| Date: | Tue, 19.07.2016 |
| 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. Friedrich Aumayr |
| Central charges in nongeometric phases from supersymmetric localization |
| Speaker: | Mauricio Romo (IAS Princeton) |
| Date: | Wed, 20.07.2016 |
| Time: | 10:00 |
| Duration: | 60 min |
| Location: | SEM DB 10 gelb, TU Wien, Freihaus, 10th floor (Wiedner Hauptstr. 8-10, A-1040 Vienna) |
| Contact: | Johanna Knapp |
| From GLSM matrix factorizations to monodromy matrices |
| Speaker: | David Erkinger (TU Wien) |
| Date: | Wed, 20.07.2016 |
| Time: | 11:30 |
| Duration: | 60 min |
| Location: | SEM DB 10 gelb, TU Wien, Freihaus, 10th floor (Wiedner Hauptstr. 8-10, A-1040 Vienna) |
| Contact: | Johanna Knapp |
| Modularity at the conifold point of the mirror quintic? |
| Speaker: | Emanuel Scheidegger (Freiburg) |
| Date: | Wed, 20.07.2016 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | SEM DB 10 gelb, TU Wien, Freihaus, 10th floor (Wiedner Hauptstr. 8-10, A-1040 Vienna) |
| Contact: | Johanna Knapp |
| Categorical Kaehler Geometry |
| Speaker: | Pranav Pandit (Uni Wien) |
| Date: | Wed, 20.07.2016 |
| Time: | 15:30 |
| Duration: | 60 min |
| Location: | SEM DB 10 gelb, TU Wien, Freihaus, 10th floor (Wiedner Hauptstr. 8-10, A-1040 Vienna) |
| Contact: | Johanna Knapp |
| Optical magnetoelectric effect and directional dichroism at the spin-wave resonances of multiferroics |
| Speaker: | David Szaller (Budapest University of Technology and Economics) |
| Abstract: | In physical systems simultaneously breaking time-reversal and spatial inversion symmetries the strength of absorption for two counter-propagating light beams can be different. This phenomenon is irrespective of the polarization state of light and is termed non-reciprocal directional dichroism. Until recent experiments on multiferroic materials this effect was generally found to be weak.
Directional dichroism in the far-infrared spectral range is the consequence of the optical magnetoelectric effect, i.e. the coupled dynamics of spins and local electric dipoles.
Our recent studies on several multiferroic compounds show that magnetoelectric spin excitations efficiently generate directional optical anisotropy leading to one-way transparency. Unidirectional optical properties, present in a large variety of multiferroic materials, can open a new horizon in photonics. |
| Date: | Wed, 20.07.2016 |
| Time: | 16:00 |
| Duration: | 45 min |
| Location: | Seminarraum DC rot 07 (Freihaus, roter Bereich, 7. OG), Wiedner Hauptstraße 8-10, 1040 Wien |
| Contact: | Andrei Pimenov |
| N=2 current and anomaly multiplets: Quantum central charges |
| Speaker: | Robert Wimmer (Americal Physical Society, Ridge, New York) |
| Abstract: | We study in detail the structure of possible currents and anomalies in N=2
supersymmetric theories that have states with nontrivial topological
(central) charges, like (confined) monopoles and non-abelian vortices. We
compare the anomalies in these theories with quantum corrections of the
central charges and show how they contribute to these corrections. |
| Date: | Thu, 21.07.2016 |
| Time: | 14:00 |
| Location: | ITP, TU Wien, Seminar room DB-gelb-10, Wiedner Hauptstr. 8-10, 1040 Wien |
| Contact: | Anton Rebhan |
| Speaker: | Dr. Ruggero Bandiera (U Rome, La Sapienza) |
| Abstract: | We shall review Getzler's construction of the higher Deligne groupoid
of a dg Lie (or more in general L-infinity) algebra,
and its role in deformation theory and rational homotopy theory. |
| Date: | Fri, 22.07.2016 |
| Time: | 11:30 |
| Duration: | 60 min |
| Location: | Erwin Schrödinger International Institute, Boltzmanngasse 9, 1090 Wien, Boltzmann lecture hall |
| Contact: | secr@esi.ac.at |
| The role of quantum information in thermodynamics- recent progress |
| Speaker: | Marcus Huber (Universität Wien) |
| Abstract: | Information is already at the heart of classical thermodynamics. Whether we call energy heat or work, i.e. whether we can use it for useful tasks depends on our knowledge of the state of the system and the exact evolution. This connection becomes even deeper at the quantum scale, where furthermore new questions arise: what is the role and impact played by genuine quantum concepts, such as entanglement, in the foundations and practical applications of thermodynamics. I will briefly survey recent progress along different lines of research and end with an exemplary discussion of quantum refrigerators and experimental proposals for building useful ones.
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| Date: | Fri, 22.07.2016 |
| Time: | 15:30 |
| Location: | Atominstitut, Hörsaal, Stadionallee 2, Wien 2 |
| Contact: | P. Schneeweiß |
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