Calendar of Physics Talks Vienna

Dynamical generation of fuzzy extra dimensions
Speaker:Clemens Kerschbaumer (Univ. Wien)
Abstract:im Rahmen des Seminars für Mathematische Physik: In this talk, a renormalizable gauge theory model will be discussed which exhibits higher dimensions. It will be shown that under certain conditions, fuzzy spheres arise as extra dimensions. Some of these configurations will be investigated in detail by elaborating the Kaluza-Klein modes. Literature: hep-th/0606021
Date: Tue, 16.12.2014
Time: 14:15
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:H. Steinacker

Temporal aspects of the photoelectric effect in solids
Speaker:Dr. Luca Castiglioni (University of Zurich, Department of Physics, Zurich/Switzerland)
Abstract:The energetics of the photoelectric effect has been understood for a long time and photoelectron spectroscopy has become the preeminent tool to study the electronic structure of matter. The recent advent of optical pulses with attosecond time resolution has allowed the direct study of temporal aspects of the photoelectric effects. Pioneering experiments in noble gas atoms and condensed matter revealed that photoemission is not instantaneous and that a short time elapses between photon absorption and emission of the electron. The few existing experiments were only able to assess relative delays between electrons emitted from different initial states due to lack of a proper temporal reference. We present an interferometric method that uses an external reference process to derive energy-dependent photoemission delays from solid surfaces. We studied noble metal surfaces and found an unexpec
Date: Tue, 16.12.2014
Time: 16:00
Location:Technische Universität Wien, Institut für Angewandte Physik, E134 yellow tower „B“, 5th floor, Seminarraum 134A (room number DB05L03), 1040 Wien, Wiedner Hauptstraße 8-10
Contact:Ao.Univ.Prof. Dr. Wolfgang Werner

Effective field theory methods and direct detection of dark matter
Speaker:Massimiliano Procura (Univ. Wien)
Abstract:Im Rahmen des Teilchenphysikseminars: I will discuss two applications of effective field theory methods in the context of direct detection of dark matter. In the absence of light mediators in the dark sector we parameterize the interactions of dark matter with Standard Model fields via non-renormalizable operators suppressed by powers of the mediator mass scale. We perform a systematic renormalization group evolution analysis from this New Physics scale down to the hadronic scale elevant for direct detection. This allows us to put novel constraints on Wilson coefficients that neglecting Standard Model loop effects could not be extracted from direct detection bounds.In the second part of the talk, I will discuss a novel determination of the proton and neutron scalar couplings that are input quantities for direct searches.
Date: Tue, 16.12.2014
Time: 16:15
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:A. Hoang

Thermal Hadronization and Hawking-Unruh Radiation in QCD
Speaker:Paolo Castorina (Catania University and INFN Catania)
Abstract:The thermal multihadron production observed in different high energy collisions poses many basic problems: why do even elementary, e+e− and hadron-hadron, collisions show thermal behaviour? Why is there in such interactions a suppression of strange particle production? Why does the strangeness suppression almost disappear in relativistic heavy ion collisions? Why in these collisions is the thermalization time less than ≃ 0.5 fm/c? Why are there freeze-out criteria related to the energy density and entropy density per produced particle? One shows that the recently proposed mechanism of thermal hadron production through Hawking-Unruh radiation can naturally answer the previous questions. Indeed, the interpretation of quark - antiquark pairs production, by the sequential string breaking, as tunneling through the event horizon of colour confinement leads to thermal behavior... [abridged]
Date: Thu, 18.12.2014
Time: 14:00
Duration: 60 min
Location:SEM 136, TU Wien, Freihaus, 10th floor (Wiedner Hauptstr. 8-10, A-1040 Vienna)
Contact:Daniel Grumiller

Multiferroics: A Daydream?
Speaker:Maximilien Cazayous (Université Paris Diderot, France)
Abstract:The revival of the magnetoelectric effect is due to the recent surge of interest for a family of very attractive materials in which both ferroelectric and magnetic orders are present. These materials, known as multiferroics, have attracted much attention worldwide. Multiferroic materials are prime candidates for the manipulation of spin states via electric fields and the tuning of dielectric properties via magnetic fields, both very desirable for applications. I will introduce this theme through the main discoveries of these last years and with regard to the numerous fundamental questions. I will show how the application perspectives extend the potential of this multifunctional material to transform information from one state variable into another (e.g., charge, spin, light, etc).
Date: Fri, 19.12.2014
Time: 14:30
Duration: 45 min
Location:Seminar Room CBEG02 (387, Photonics); Gußhausstraße 27
Contact:Andrei Pimenov