CPT

Calendar of Physics Talks Vienna

Time-Resolved Photoemission on the Attosecond Scale
Speaker:Renate Pazourek (Vienna University of Technology)
Abstract:One of the most fundamental processes in the interaction of light with matter is the photoelectric effect, i.e. the emission of an electron after the absorption of a photon. With the advent of ultrashort and well-controlled laser pulses photoemission can now be studied with unprecedented temporal resolution. The challenge lies in interpreting the timing information obtained by attosecond pump-probe experiments. One fundamental question is whether an electron is emitted instantaneously upon absorption of a photon or with a certain time shift. For an accurate theoretical description we numerically solve the time-dependent Schrödinger equation for one- and two-electron atoms and can show that, as long as all measurement-induced distortions can be quantified, the intrinsic (Eisenbud-Wigner-Smith) time delay of photoemission becomes accessible by attosecond pump-probe setups.
Date: Tue, 29.10.2013
Time: 12:30
Duration: 60 min
Location:Vienna University of Technology, Wiedner Hauptstr. 8-10, yellow area, 10th floor, seminar room E136
Contact:Iva Lovrekovic, Albert Georg Passegger - www.univie.ac.at/lunch-seminar

Inertial Electrostatic Confinement Fusion
Speaker:Daniel R. Knapp (Medical University of South Carolina, Charleston, SC, USA)
Abstract:Inertial electrostatic confinement (IEC) fusion is an approach to nuclear fusion that uses electrostatic acceleration of ions to fusion relevant energies rather than thermal heating. While it is relatively easy to accelerate ions to kinetic energies (a few tens of keV) equivalent to those in plasmas of several hundred million degrees, the challenge is to achieve useful levels of fusion before the ions thermalize. Some theoretical studies have argued that IEC fusion can never yield net energy, but there are continuing efforts by credible groups toward IEC-based reactors for energy production. IEC also has non-energy applications, and these applications drive most of the current work. The history and current work in IEC fusion will be reviewed, and some initial simulation studies on a new design for a compact IEC fusion reactor will be presented.
Date: Tue, 29.10.2013
Time: 14:15
Location:Institute for Theoretical Physics – Vienna University of Technology Wiedner Hauptstraße 8 – 10, 10th floor, B (yellow tower)
Contact:Ass. Prof. Dr. Christoph Lemell

Retinal blood flow measurements with dual beam Fourier-domain optical coherence tomography
Speaker:Dipl.-Ing. Veronika Doblhoff-Dier (TU Wien, IAP und Zentrum für Medizinische Physik und Biomedizinische Technik, Medizinische Universität Wien)
Abstract:A number of ocular diseases are related to abnormal blood flow in the eye. Consequently, methods to quantify the total retinal blood flow have seen increased interest in recent years. This presentation will illustrate the principles and application of a novel dual-beam Fourier-Domain Doppler Optical Coherence Tomograph combined with a commercial Retinal Vessel Analyzer. The system allows measuring the human retinal blood flow in all the eye's larger vessels in vivo. The presentation will cover the basic physical methods behind this setup, its experimental implementation and the achieved results.
Date: Tue, 29.10.2013
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:Ao.Univ.Prof. Dr. Martin Gröschl

A cold-atom random laser
Speaker:Robin KAISER (Institut Non-Linéaire de Nice, France)
Abstract:Atoms can scatter light and they can also amplify it by stimulated emission. From this simple starting point, we study how to realize a random laser in a cloud of laser-cooled atoms. The answer is not obvious [1] as both processes (elastic scattering and stimulated emission) seem to exclude one another: pumping atoms to make them behave as an amplifier reduces drastically their scattering cross-section. Here we show experimental realizations of lasing with cold atoms in a cavity [2] and without external mirrors (random lasing) [3]. [1] L. Froufe-Prez, W. Guerin, R. Carminati and R. Kaiser, Phys. Rev. Lett. 102, 173903 (2009). [2] W. Guerin, F. Michaud and R. Kaiser, Phys. Rev. Lett. 101, 093002 (2008). [3] Q. Baudouin, N. Mercadier, V. Guarrera, W. Guerin, R. Kaiser Nature Physics 9, 357 (2013).
Date: Thu, 31.10.2013
Time: 10:30
Location:TU Wien Atominstitut, Hörsaal, Stadionallee 2, 1020 Wien
Contact:Arno Rauschenbeutel

Locally covariantfield theory
Speaker:Jochen Zahn (Univ. Wien)
Abstract:im Rahmen des Literatursemeniars der Gravitationsphysik
Date: Thu, 31.10.2013
Time: 14:15
Duration: 60 min
Location:Arbeitsgruppe: Gravitation, Währinger Strasse 17, Seminarraum A, 2. Stock
Contact:H. Rumpf

After the discovery: challenges and open questions in Higgs physics
Speaker:Christophe Grojean (CERN and IFAE, Barcelona)
Abstract:im Rahmen des Teilchenphysikseminars
Date: Thu, 31.10.2013
Time: 14:15
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:A. Hoang, P. Pietrulewicz