|
Calendar of Physics Talks Vienna
Picosecond photocurrents and terahertz generation in nanoscale circuits |
Speaker: | Alexander W. Holleitner (Walter Schottky Institute and Physik-Department, TUM) |
Abstract: | The time-resolved dynamics of photogenerated charge carriers in nanoscale systems are typically detected by optical methods such as the transient absorption technique and the time-resolved photoluminescence spectroscopy. Many questions remain concerning the separation and transport of photogenerated charge carriers to source and drain leads, when the nanosystems shall be functional modules in (opto-)electronic circuits. Typical propagation times of ballistic photogenerated charge carriers in nanoscale circuits are in the ps-regime. Conventional electronic measurements cannot resolve such ultrafast dynamics because available electronic equipment cannot produce trigger signals and detect transients faster than tens of picoseconds. Furthermore, nanosystems typically exhibit a high impedance of several kilo-ohms, and ultrafast charge-carrier dynamics are therefore obscured by the response ti |
Date: | Mon, 18.06.2012 |
Time: | 17:30 |
Duration: | 60 min |
Location: | TU Wien, Schütte-Lihotzky Hörsaal, HS 7, Karlsplatz 13, 1040 Wien |
Contact: | Dr. Christiane Losert / Univ. of Vienna |
Yang-Mills Theory at Non-Vanishing Temperature |
Speaker: | Leonard Fister (Universität Heidelberg) |
Abstract: | We study the temperature dependence of correlators in Yang-Mills theory. For this purpose we utilise a purely thermal renormalisation group flow equation, and obtain the full thermal propagators. Interestingly, the electric screening mass is sensitive to the confinement-deconfinement phase transition. We also compute thermodynamic quantities such as the pressure. |
Date: | Tue, 19.06.2012 |
Time: | 12:30 |
Duration: | 60 min |
Location: | TU Wien ( Wiedner Hauptstr. 8-10, yellow area, 10th floor, seminar room E136 ) |
Contact: | Vienna Theory Lunch Seminar (http://www.univie.ac.at/lunch-seminar/) |
Die Renormierungsgruppe in der störungstheoretischen AQFT |
Speaker: | Christian Köhler |
Abstract: | im Rahmen des Seminars für Mathematische Physik |
Date: | Tue, 19.06.2012 |
Time: | 14:15 |
Duration: | 60 min |
Location: | Fakultät für Physik, Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
Contact: | J. Yngvason |
On the emission of secondary electrons from solids - Coincidence experiments and dielectric formalism |
Speaker: | Dipl.-Ing. Francesc Salvat-Pujol (Technische Universität Wien, Institut für Angewandte Physik) |
Abstract: | The emission of secondary electrons (SE) from solid surfaces is a physical phenomenon which has been known for over a hundred years. It plays a relevant role in a number of applications, for instance in particle-detector technology (channeltrons, microchannel plates, photomultiplier tubes, etc.). In charged-particle accelerators, the presence of a cloud of SE emitted from the walls of the accelerator affects the stability of the particle beam. Similarly, SE emission critically affects the charge balance in electronic devices such as plasma displays.
In spite of its widespread use, the mechanisms responsible for SE emission are far from being understood on a detailed and quantitative level: recent independent measurements of the SE yield from aluminum under electron bombardment exhibit discrepancies of as much as a factor of seven. In this seminar talk I will present the outcome of a series of measurements of SE emission in coincidence with selected energy losses of backscattered electrons from several materials. The experimental data give insight into the mechanisms responsible for SE emission in an unprecedented detail. The interpretation of the measured data is supported by Monte Carlo simulations of electron transport. A brief overview of the semiclassic dielectric formalism used to describe energy losses (both in the bulk of the medium and in the surface region) will be given in addition, paying special attention to highlight surface excitations and the role they play in SE emission.
|
Date: | Tue, 19.06.2012 |
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: | Ao.Univ.Prof. Dr. Wolfgang Werner |
Exploring the Energy Frontier- Latest Results from the LHC |
Speaker: | Claudia-Elisabeth Wulz (Institut für Hochenergiephysik) |
Abstract: | The excellent performance of the Large Hadron Collider has so far
led to more than 10 inverse femtobarn of proton-proton collision
events delivered to each of the general-purpose experiments ATLAS
and CMS. In 2012 the centre-of-mass energy was raised from 7 to
8 TeV, currently the highest energy ever achieved by an accelerator,
which will enable to explore new frontiers. A large number of topics
is being studied, ranging from standard model physics to exotica.
Interesting results in the field of the standard model will be presented,
including the status of the search for the Higgs boson in
several decay channels. |
Date: | Wed, 20.06.2012 |
Time: | 17:00 |
Duration: | 60 min |
Location: | Institut für Hochenergiephysik, 1050 Wien, Nikolsdorfer Gasse 18, Bibliothek, 1. Stock |
Contact: | Ken Suzuki, 01 4277 29725 |
General relativistic effects in quantum interference |
Speaker: | Magdalena Zych (Vienna) |
Abstract: | im Rahmen des Literaturseminars |
Date: | Thu, 21.06.2012 |
Time: | 14:15 |
Duration: | 60 min |
Location: | Arbeitsgruppe: Gravitation, Währinger Strasse 17, Seminarraum A, 2. Stock |
Contact: | R. Beig |
Computational uncertainties in public BR (B → Xs γ) codes |
Speaker: | Sebastian Frank (HEPHY, Wien) |
Abstract: | im Rahmen des Teilchenphysikseminars |
Date: | Thu, 21.06.2012 |
Time: | 14:15 |
Duration: | 60 min |
Location: | Fakultät für Physik, Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
Contact: | A. Hoang, H. Neufeld |
Speaker: | Christos Tsiapalis (Med.Univ.Wien) |
Abstract: | im Rahmen der gemeinsam veranstalteten Seminare |
Date: | Fri, 22.06.2012 |
Time: | 14:15 |
Duration: | 90 min |
Location: | Medizinische Universität Wien, Informatikbibliothek Bauteil 88, E 03, Spitalgasse 23 |
Contact: | H. Hüffel, Stefan Thurner |
Results on the Chameleon fields |
Speaker: | Guillaume PIGNOL (Lab. de Physique Subatomique & Cosmologie, Grenoble) |
Date: | Fri, 22.06.2012 |
Time: | 15:30 |
Location: | TU Wien Atominstitut, Hörsaal, Stadionallee 2, 1020 Wien |
Contact: | H. Abele |
|