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Calendar of Physics Talks Vienna
| Attosecond photonics: what we learn by transforming many photons into one |
| Speaker: | Paul CORKUM (University of Ottawa and National Research Council of Canada) |
| Abstract: | The extreme nonlinear optics that underlies attosecond science is very different from perturbative nonlinear optics. Extreme nonlinear optics is understood through quantum trajectories of an ionizing electron wave packet. A trajectory begins from a bound state and returns to the same state, following an excursion in the continuum.
Quantum trajectories map onto an interferometer – an electron interferometer created by light. A weak additional field can perturb these trajectories, manipulating the interferometer while simultaneously constructing a perturbative nonlinear optics on top of the extreme process. Using interferometric concepts, I will show how we can measure the space-time properties of attosecond pulses and the the space-time structure of electronic wave packets.
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| Date: | Mon, 19.11.2012 |
| Time: | 17:30 |
| Location: | TU Wien Freihaus, Hörsaal 5 (2. Stock, grüner Bereich), Wiedner Hauptstr. 8, 1040 Wien |
| Contact: | J. Schmiedmayer |
| Infrateilchen und Teilchengewichte in der lokalen Quantenphysik |
| Speaker: | Albert Georg Passegger (Univ.Wien) |
| Abstract: | im Rahmen des Seminars für Mathematische Physik |
| Date: | Tue, 20.11.2012 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | J. Yngvason |
| Electrodes for Dye-Sensitized Solar Cells: A Case of Titanium Dioxide and Graphene |
| Speaker: | Prof. Ladislav Kavan (J. Heyrovsky Institute of Physical Chemistry, Prague/Czech Republic) |
| Abstract: | The growing world’s demand for electricity, confronted with inherent limitations of fossil and nuclear fuels, point at renewable resources to be the realistic energetic perspective for the society. Sun is unique source of renewable energy, providing the requested terawatt power in a global scale.
The dye sensitized solar cell (DSC) is an alternative to Si-based photovoltaics; it is favored by low cost and ease of fabrication. The generic device is a photoelectrochemical DSC with nanocrystalline TiO2 photoanode, electrolyte redox mediator and a cathode. The latter is typically a film of Pt nanoparticles on F-doped SnO2 (Pt-FTO) and the former is the I3-/I- in aprotic electrolyte medium. Design of TiO2 photoanode represents significant challenge for nanoscience. Recent progress in the field highlighted the (001)-oriented TiO2 (anatase) nanosheet exhibiting larger open circuit voltage in D |
| Date: | Tue, 20.11.2012 |
| Time: | 16:00 |
| Location: | Technische Universität Wien, Institut für Angewandte Physik, Seminarraum 134A, Turm B (gelbe Leitfarbe), 5. OG, 1040 Wien, Wiedner Hauptstraße 8-10 |
| Contact: | Univ.Prof. Dr. Ulrike Diebold |
| Photon accumulation near a black hole |
| Speaker: | Volker Perlick (Bremen) (joint seminar with the Pauli Institute GPRS Workshop) |
| Abstract: | In the first part of the talk a Schwarzschild black hole is considered. We assume that light sources are distributed on a (big) sphere of radius R that emit, at an instant of time, photons isotropically. We calculate the resulting photon distribution and find that in the long-time limit the density becomes infinitely large near the photon sphere at r=3m. This suggests that every Schwarzschild black hole in nature should be surrounded by a shell of very high photon density which could be detrimental to the health of any observer who comes close to this region. In the second part we discuss how the situation changes if a Kerr black hole is considered. -- The first part is based on the Bachelor Thesis of Dennis Philipp and the second part is ongoing work with Arne Grenzebach. |
| Date: | Wed, 21.11.2012 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Wolfgang Pauli Institut, Seminarraum C715, Nordbergstrasse 15/7/C, 1090 Wien |
| Contact: | P. Chrusciel |
| Hadronic contributions to the muon g-2 |
| Speaker: | Richard Williams (University of Graz) |
| Abstract: | A several year old discrepancy at the 2-3 sigma level between
precision Standard Model computations of the muon‘s magnetic
moment and experimental measurement defies theory. I quickly
review the last measurements, the various contributions to the
theory estimate that include a mind-boggling 5-loop QED calculation
as well as high-order QCD and electroweak corrections,
and concentrate especially on the hadronic contributions. I will
show how progress in the Dyson-Schwinger formulation of
Chromodynamics provides a cross-check, extension and improvement
over future lattice and existing quark model and
effective Lagrangian estimates, highlighting the strengths
and weaknesses of the various approaches. |
| Date: | Wed, 21.11.2012 |
| Time: | 17:00 |
| Duration: | 60 min |
| Location: | Stefan Meyer Institute for subatomic physics, Boltzmanngasse 3, 1090, Raum 2.08 |
| Contact: | Ken Suzuki, 01 4277 29725 |
| High optical depth off-resonance Raman memory in presence of losses |
| Speaker: | Nir S. KAMPEL (Nils Bohr Institute, Kopenhagen, Denmark) |
| Abstract: | Quantum memory has many applications, such as a source for a single photon on demand and a quantum repeater. A multimode memory has the advantage of better utilizing the resources at hand. A high optical depth is required for high total efficiency and a multimode capacity of the memory. For this reason we have realized the off resonance Raman memory scheme with high optical depth (up to 200) using ultra-cold Rubidium 87 trapped in a magnetic trap.
Here we are presenting the total efficiency dependence on the optical depth and the power of the control beam in the presence of losses. In addition we have implemented a balanced homodyne imaging technique and measured the outgoing signal beam spatio-temporal mode, enabling up to 30 independent spatial modes.
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| Date: | Thu, 22.11.2012 |
| Time: | 11:00 |
| Location: | Hörsaal Atominstitut, Stadionallee 2, 1020 Wien |
| Contact: | Arno Rauschenbeutel |
| Finite flavour groups of fermions |
| Speaker: | Walter Grimus (Univ.Wien) |
| Abstract: | im Rahmen des Teilchenphysikseminars |
| Date: | Thu, 22.11.2012 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | H. Neufeld |
| Quantum many-body effects in nanosystems |
| Speaker: | Sabine Andergassen (Univ.Wien) |
| Abstract: | im Rahmen der gemeinsam veranstalteten Seminare "Komplexe Stochastische
Systeme" (Univ.Wien) und "Analyse Komplexer Systeme" (Med.Univ.Wien) |
| Date: | Fri, 23.11.2012 |
| Time: | 14:15 |
| Duration: | 45 min |
| Location: | Fakultät für Physik, Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | H. Hüffel, Stefan Thurner |
| Finite-Frequency Noise and AC Conductance of a Kondo Quantum Dot |
| Speaker: | Sarah Mueller (Univ.Wien) |
| Abstract: | im Rahmen der gemeinsam veranstalteten Seminare "Komplexe Stochastische
Systeme" (Univ.Wien) und "Analyse Komplexer Systeme" (Med.Univ. Wien) |
| Date: | Fri, 23.11.2012 |
| Time: | 15:00 |
| Duration: | 45 min |
| Location: | Fakultät für Physik, Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | H. Hüffel, Stefan Thurner |
| Quantum criticality - quantum WHAT? |
| Speaker: | Silke BÜHLER-PASCHEN (Institut für Festkörperphysik TU Wien) |
| Abstract: | What is quantum criticality? In which settings can it be observed? Which consequences does it have?And what is so special about it? After discussing these general questions I will introduce heavy fermion compounds. These intermetallic compounds have been detrimental in establishing the field of quantum criticality as their low-lying and competing energy scales make them readily tunable. While the quantum critical behavior of some heavy fermion materials may be understood using a space-time generalization of classical criticality, often called Hertz-Millis theory, for other materials a new framework appears to be required. This suggests that quantum criticality in heavy fermion materials is non-universal. Combining investigations of heavy fermion coumpounds of different dimensionality we are able to suggest a materials-based global phase diagram - a precondition for a unified theoretical description. |
| Date: | Fri, 23.11.2012 |
| Time: | 15:30 |
| Location: | Hörsaal Atominstitut, Stadionallee 2, 1020 Wien |
| Contact: | J. Schmiedmayer |
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