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Calendar of Physics Talks Vienna
Coherence effects in light transport: Dicke vs Anderson localization |
Speaker: | Robin Kaiser (CNRS) |
Abstract: | The quest for Anderson localization of light is at the center of many experimental and theoretical activities. Cold atoms have emerged as interesting quantum system to study coherent transport properties of light. Initial experiments have established that dilute samples with large optical thickness allow studying weak localization of light. The goal of our research is to study coherent transport of photons in dense samples. One important aspect is the quest of Anderson localization of light with cold atoms and its relation to Dicke super- or subradiance. With large and dense samples of cold atoms the interplay between these different phenomena can be studied. In this talk I will give an overview on our research and present results on cooperative scattering of light by cold atoms. |
Date: | Mon, 26.03.2012 |
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 |
Preparing projected entangled pair states on a quantum computer |
Speaker: | Martin Schwarz (University of Vienna) |
Abstract: | We present a quantum algorithm to prepare injective PEPS on a quantum computer. To be efficient, our algorithm requires well-conditioned PEPS projectors and, essentially, an inverse-polynomial spectral gap of the PEPS' parent Hamiltonian. Injective PEPS are the unique groundstates of their parent Hamiltonians and capture groundstates of many physically relevant many-body Hamiltonians, such as e.g. the 2D AKLT state. Even more general is the class of G-injective PEPS where symmetry group G acting on virtual tensor indices leaves the PEPS invariant. G-injective PEPS are powerful enough to represent topologically ordered quantum states. As our second result we show how to prepare G-injective PEPS under similar assumptions as well. |
Date: | Tue, 27.03.2012 |
Time: | 12:30 |
Duration: | 60 min |
Location: | Vienna University of Technology: Wiedner Hauptstr. 8-10, 10th floor (yellow), seminar room E136 |
Contact: | Vienna Theory Lunch Seminar (http://www.univie.ac.at/lunch-seminar/) |
Störungstheoretische AQFT: Ein erster Überblick über Störungstheorie II |
Speaker: | Jan Schlemmer (Univ. Wien) |
Abstract: | im Rahmen des Seminars für Mathematische Physik |
Date: | Tue, 27.03.2012 |
Time: | 14:15 |
Duration: | 60 min |
Location: | Fakultät für Physik, Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock, 1090 Wien |
Contact: | J. Yngvason |
Existence of time functions |
Speaker: | Albert Fathi (ENS Lyon, et Inst. Univ. de France) |
Abstract: | im Rahmen des Literaturseminars |
Date: | Thu, 29.03.2012 |
Time: | 14:15 |
Duration: | 60 min |
Location: | Arbeitsgruppe: Gravitation, Währinger Strasse 17, Seminarraum A, 2. Stock |
Contact: | R. Beig |
Linking models with data: the Nelder-Mead method |
Speaker: | Patrick Ludl (Univ.Wien) |
Abstract: | im Rahmen des Teilchenphysikseminars |
Date: | Thu, 29.03.2012 |
Time: | 14:15 |
Duration: | 60 min |
Location: | Fakultät für Physik, Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock, 1090 Wien |
Contact: | W. Grimus, H. Neufeld |
Moving Quark in a Viscous Fluid |
Speaker: | Ali Davody (IPM Teheran) |
Abstract: | After reviewing basic aspects of Fluid/Gravity correspondence and holographic computation of drag force exerted on a quark moving through an N=4 SYM, we study the rate of energy loss of a heavy quark in the hydrodynamic regime. We use fluid/gravity duality and construct a perturbative procedure to find the string solution in gravity side. We apply this procedure to a transverse quark in Bjorken flow and compute viscous corrections to the drag force. |
Date: | Thu, 29.03.2012 |
Time: | 16:00 |
Duration: | 60 min |
Location: | SEM 136 (Freihaus, Wiedner Hauptstrasse 8-10), Institute for Theoretical Physics, Vienna University of Technology |
Contact: | Daniel Grumiller |
Emergence of Ornstein-Uhlenbeck processes from large mechanical system with random initial data |
Speaker: | Maximilian Sadilek (Univ. Wien) |
Abstract: | im Rahmen der gemeinsam veranstalteten Seminare "Komplexe Stochastische
Systeme" (Univ.Wien) und "Analyse Komplexer Systeme" (Med.Univ.Wien) |
Date: | Fri, 30.03.2012 |
Time: | 14:00 |
Duration: | 60 min |
Location: | Fakultät für Physik, Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock, 1090 Wien |
Contact: | H. Hüffel, Stefan Thurner |
White noise limits of multiplicative colored noise |
Speaker: | Florentin Harbich (Univ.Wien) |
Abstract: | im Rahmen der gemeinsam veranstalteten Seminare "Komplexe Stochastische Systeme" (Univ.Wien) und Analyse Komplexer Systeme" (Med.Univ.Wien) |
Date: | Fri, 30.03.2012 |
Time: | 15:15 |
Duration: | 60 min |
Location: | Fakultät für Physik, Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
Contact: | H. Hüffel, Stefan Thurner |
Nonthermal fixed points, topological excitations, and superfluid turbulence in an ultracold Bose gas |
Speaker: | Thomas Gasenzer (Universität Heidelberg ) |
Abstract: | Turbulence appears in situations where, e.g., an energy flux goes from large to small scales where finally the energy is dissipated.
As a result the distribution of occupation numbers of excitations follows a power law with a universal critical exponent.
The situation can be described as a nonthermal fixed point of the dynamical equations. Single-particle momentum spectra for a dynamically
evolving Bose gas are analysed using semi-classical simulations. These give information about possible universal scaling behaviour.
The connection of this scaling with the appearance of topological excitations such as solitons and vortices is discussed. For the one-dimensional case,
a random-soliton model provides analytical results for the spectra, and their relation to those found in a field-theory approach to strong wave turbulence
is discussed. The results open a view on solitary wave dynamics from the point of view of critical phenomena far from thermal equilibrium
and on a possibility to study this dynamics in experiment without the necessity of detecting solitons in situ. |
Date: | Fri, 30.03.2012 |
Time: | 15:30 |
Location: | Seminarraum Atominstitut |
Contact: | Eva Haberl, Atominstitut |
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