Calendar of Physics Talks Vienna

Electron Microscopy of Ultracold Quantum Gases
Speaker:Prof. Dr. Herwig Ott (University of Kaiserslautern, Germany)
Abstract:Scanning electron microscopy is routinely used to study solid objects on a nanometer scale. Applied to ultracold quantum gases it constitutes a powerful imaging and manipulation technique that combines single atom sensitivity with high spatial resolution. We have adapted a scanning electron microscope for the study of Bose-Einstein condensates of rubidium atoms. The focussed electron beam ionizes the atoms which are subsequently detected. The technique allows for high precision density measurements of the trapped gas with a spatial resolution of better than 150 nm. Loading the condensate in a two-dimensional optical lattice with 600 nm period we demonstrate single site addressability and show that one can produce arbitrary patterns of occupied lattice sites. Such micro-structured quantum gases might become a versatile resource for the study of mesoscopic quantum systems and future applications in quantum simulation and quantum information processing. The electron beam can also be used to locally introduce losses, thus paving the way to investigate dissipative processes in quantum gases. Ultimately, we want to employ this technique to get in situ access to the quantum correlations of bulk, lattice and low-dimensional quantum systems.
Date: Mon, 22.03.2010
Time: 17:30
Duration: 60 min
Location:Schütte-Lihotzky-HS No. 7, Karlsplatz 13, 1040 Wien
Contact:Prof. Jörg Schmiedmayer

Privacy amplification, message authentication and randomness extractors
Speaker:Jan Bouda (Uni Brno)
Abstract:Lunch Club Overview
Date: Tue, 23.03.2010
Time: 12:30
Duration: 60 min
Location:University of Vienna, Boltzmanngasse 5, 5th Floor, Large Seminar Room
Contact:Theo Adaktylos, David Burke, Andreas Gabriel, Niklas Johansson & Christoph Spengler

Thermalization in quasi-1D ultracold atomic gases
Speaker:Igor Mazets (TU Wien) (Fakultät für Physik)
Abstract:im Rahmen des Seminars für Mathematische Physik
Date: Tue, 23.03.2010
Time: 14:15
Duration: 60 min
Location:Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:J. Yngvason

Diffraction of backscattered electrons at crystal surfaces
Speaker:Dr. Aimo Winkelmann (Max-Planck-Institut für Mikrostrukturphysik, Halle (Saale)/D)
Abstract:Electron backscatter diffraction (EBSD) has developed into a valuable tool for the analysis of materials in the scanning electron microscope (SEM) [1]. Pronounced improvements in applications of the EBSD method can be expected if it is possible to gain access to a quantitative description of not only the total number of backscattered electrons, but also to the fine-scale angular variations observed as diffraction patterns of these electrons. A complete simulation of the observed intensities, however, is only possible by applying electron diffraction theories that can properly include the multiple (dynamical) scattering of keV electrons in crystals [2,3]. I will discuss the application of many-beam dynamical theory to the simulation of experimental diffraction patterns of backscattered electrons. By energy-resolved measurements, the correlation between the energy loss of the scattered electrons and their diffraction effects can be investigated. First experimental results of corresponding angle-resolved reflection electron energy loss measurements are presented [4]. It is shown that under certain conditions, inelastically backscattered electrons can show more pronounced diffraction effects than the elastic electrons. 1. A.J. Schwartz, M. Kumar, B.L. Adams, D. P. Field (Eds.), Electron Backscatter Diffraction in Materials Science, 2nd edition, Springer, Berlin, 2009 2. A. Winkelmann, C. Trager-Cowan, F. Sweeney, A. P. Day, P. Parbrook, Ultramicroscopy 107, 414 (2007) 3. A. Winkelmann, Ultramicroscopy 108, 1546 (2008) 4. M. R. Went, A. Winkelmann, M. Vos, Ultramicroscopy 109, 1211 (2009)
Date: Tue, 23.03.2010
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. Wolfgang Werner

Relativistic two-particle entanglement
Speaker:Nicolai Friis (Univ. Wien) (Fakultät für Physik)
Abstract:im Rahmen des Teilchenphysikseminars
Date: Thu, 25.03.2010
Time: 14:15
Duration: 60 min
Location:Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:R.A. Bertlmann, H. Neufeld

Minimally non-linear systems: Toy genetic regulatory network dynamics at the edge of chaos
Speaker:Rudolf Hanel (Med. Univ. Wien) (Fakultät für Physik)
Abstract:im Rahmen der gemeinsam veranstalteten Seminare "Komplexe Stochastische Systeme"(Univ. Wien) und "Analyse Komplexer Systeme" (Med.Univ.Wien)
Date: Fri, 26.03.2010
Time: 14:30
Duration: 90 min
Location:Medizinische Univ., Bauteil 86 (Zugang über Spitalgasse 23) Ebene 2
Contact:H. Hüffel