Calendar of Physics Talks Vienna

Wave-optical X-ray Imaging for Biomedical Applications
Speaker:Franz Pfeiffer (Technical University Munich, 85748 Garching/ Munich, Germany)
Abstract:The basic principles of x-ray image formation in radiography have remained essentially unchanged since Röntgen first discovered x-rays over a hundred years ago. The conventional approach relies on x-ray attenuation as the sole source of contrast and draws exclusively on ray or geometrical optics to describe and interpret image formation. This approach ignores another, potentially more useful source of contrast, namely the phase information. Phase-contrast imaging techniques, which can be understood using wave optics rather than ray optics, offer ways to augment or complement standard attenuation contrast by incorporating phase information. This presentation will review the recent development of phase-contrast imaging in general, and focus particularly on our contributions to the development of grating-based x-ray phase-contrast computed tomography. A variety of experimental results will be shown that highlight the potential of this novel method for biomedical, clinical, and industrial applications. The presentation concludes with an outlook concerning the translation to pre-clincial and finally clinical practice.
Date: Mon, 10.11.2014
Time: 17:00
Duration: 90 min
Location:Universität Wien; Fakultät für Physik, Lise-Meitner-Hörsaal; Bolzmanngasse 5, 1090 Wien
Contact:Univ.Prof. Dr. Markus Arndt

Die nichtkommutative Raumzeit von Doplicher, Fredenhagen und Roberts
Speaker:Jan Schlemmer (Univ. Wien)
Abstract:im Rahmen des Seminars für Mathematische Physik: ausgehend von einer Diskussion der physikalischen Grenzen von Ortsmessungen formulierten Doplicher, Fredenhagen und Roberts 1994 ein Modell einer flachen, nichtkommutativen Raumzeit, und diskutierten einige Eigenschaften von Feldern auf dieser. In meinem Vortrag werde ich diese physikalische Überlegungen, das resultierende Raumzeitmodell und einige seiner Eigenschaften vorstellen.
Date: Tue, 11.11.2014
Time: 14:15
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:H. Steinacker

Roots of unity and the lepton mixing patterns obtainable with finite flavour symmetries
Speaker:Renato Fonseca (IFIC, Valencia)
Abstract:im Rahmen des Teilchenphysikseminars
Date: Tue, 11.11.2014
Time: 16:15
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:A. Hoang, H. Neufeld

Optical Magnetoelectric Effect and Unidirectional Light Propagation in Multiferroics
Speaker:Istvan Kezsmarki (Budapest University of Technology and Economics)
Abstract:Simultaneous breaking of time-reversal and spatial inversion symmetries can lead to the emergence of new optical phenomena in multiferroics. As the most peculiar example, we have recently found that multiferroics can exhibit strong directional dichroism, i.e. they absorb counter-propagating light beams with different strength, where the absorbing and transparent directions of propagation can be reversed by the application of either magnetic or electric fields. In the THz spectral range, directional dichroism is the consequence of the optical magnetoelectric effect, i.e. the coupled dynamics of spins and local electric dipoles. Spin-wave modes in multiferroics can be simultaneously excited by the electric and magnetic components of light, hence, they can be viewed as the “elementary excitations” of such hybrid magnetoelectric response.
Date: Wed, 12.11.2014
Time: 16:00
Duration: 45 min
Location:Seminarraum 138B, 7. OG, roter Bereich, Freihausgebäude, TU Wien, Wiedner Hauptstr.8-10
Contact:Andrei Pimenov

Self-intersecting fuzzy extra dimensions in maximally supersymmetric gauge theory (and matrix models)
Speaker:Harold Steinacker (Univ. Wien)
Abstract:im Rahmen des Literaturseminars: we explain how fuzzy geometries in extra dimensions can emerge in standard Yang-Mills gauge theory, based on a geometric version of the Higgs effect. In particular, we discuss the 4-and 6-dimensional squashed coadjoint orbits which were recently found in maximally supersymmetric N=4 SYM. The resulting low-energy fluctuation modes lead to 3 generations of chiral fermions coupled to scalar and gauge fields. The discussion is focused on geometrical and group-theoretical aspects. Talk based on arXiv:1409.1440
Date: Thu, 13.11.2014
Time: 14:00
Duration: 60 min
Location:Arbeitsgruppe Gravitation, Währinger Strasse 17, Seminarraum A, 2. Stock, 1090 Wien
Contact:P.T. Chrusciel

Solar Neutrino Spectroscopy - Success and Open Questions
Speaker:Lothar Oberauer (TU Munich)
Abstract:Solar neutrino spectroscopy was essential for the discovery of neutrino  oscillations. With the liquid  scintillator detector Borexino at the Gran Sasso underground laboratory in Italy all neutrino emitting braches of the solar pp-chain have been detected now. Recently, the first direct observation of low energy solar neutrinos from the fusion of the primary two proton reaction to deuterium was published (Nature 512, Aug. 2014). In this talk these results will be presented and discussed in the frame of neutrino oscillations and open astrophysical questions. Finally, future options with large volume liquid scintillators will be shown and discussed.
Date: Fri, 14.11.2014
Time: 10:30
Location:Seminar Room Wohllebengasse 12-14 (tea and cookies 10:15)

The Energy and Climate Challenges
Speaker:Dr. Steven Chu (Nobel Prize in Physics and former U.S. Secretary of Energy), (Stanford University)
Date: Fri, 14.11.2014
Time: 18:00
Location:Großer Festsaal of the University of Vienna
Contact:J. Schmiedmayer