CPT

Calendar of Physics Talks Vienna

Single molecule spectroscopy and reaction
Speaker:Prof. Maki Kawai (Dept. of Advanced Materials Science, University of Tokyo/Japan)
Abstract:Ultimate spatial resolution of scanning tunneling microscope (STM) enables us to observe the inner electronic, vibrational [1-5] and spin [6] structures of a molecule adsorbed on solid surfaces. Vibrational spectrum of a single molecule provides useful information not only for the chemical identification of the molecule [1] but also for investigating how molecular vibrations can couple with the relevant dynamical processes [2, 3]. The response of vibrationally mediated molecular motion to applied bias voltage, namely an “action spectrum”, can reveal vibrational modes that excited through STM inelastic tunneling processes, because the molecular motion is induced only via the inelastic tunneling processes [4]. Thus, the action spectrum would be a candidate for detecting which vibrational mode is actually excited and associated with molecular motions. The mechanism to excite vibrational modes of molecules is revealed to be a resonant mechanism [5]. A theoretical analysis of the action spectrum even enabled us to learn about the assorted excitation relevant for the reaction to occur [7]. Life-time of the vibrational excited state was found to lengthen by inserting insulator thin film of MgO, decoupling the adsorbate and metal, enabled to split water molecule by exciting the OH stretching mode [8]. [1] Y. Kim, T. Komeda, and M. Kawai, Phys. Rev. Lett. 89 (2002) 126104. S. Katano, M. Trenary, Y. Kim and M. Kawai, Science 316 (2007) 1883. [2] T. Komeda, Y. Kim, M. Kawai, et al., Science 295 (2002) 2055. [3] T. Okada, Y. Kim and M. Kawai, submitted for publication (2010). [4] Y. Sainoo, Y. Kim, T. Okawa, et al., Phys. Rev. Lett. 95 (2005) 246102. [5] M. Ohara, Y. Kim and M. Kawai, Phys. Rev. Lett. 100 (2008) 136104. [6] N. Tsukahara, K. Noto, M. Ohara, S. Shiraki, N. Takagi, Y. Takata, J. Miyawaki, M. Taguchi, A. Chainani, S. Shin and M. Kawai, Phys. Rev. Lett. 102 (2009) 167203. [7] K. Motobayashi, Y. Kim, H. Ueba and M. Kawai, Phys. Rev. Lett. 105 (2010) 07 6101. [8] H-J. Shin, J. Jung, K. Motobayashi, S. Yanagisawa, Y. Morikawa, Y. Kim and M. Kawai, Nature Materials 9 (2010) 442-447.
Date: Mon, 22.11.2010
Time: 16:00
Location:Technische Universität Wien, Institut für Angewandte Physik, Seminarraum 134, Turm B (gelbe Leitfarbe), 5. OG, 1040 Wien, Wiedner Hauptstraße 8-10
Contact:Univ.Prof. Dr. Ulrike Diebold

Quantum cascade lasers and strong light-matter coupling in the THz range
Speaker:Giacomo Scalari (Quantum Optoelectronics Group, Institute of Quantum Electronics, ETH Zurich)
Abstract:The THz portion of the electromagnetic spectrum (1-10 THz) presents a number of potential applications (imaging, chemical sensing, telecommunications among others) together with interesting opportunities in more fundamental research studies. In this talk I will discuss our groups’ recent progress in the realization and the study of quantum cascade (QC) lasers emitting at terahertz (THz) frequencies together with some strong light-matter coupling experiments involving intersubband transitions and metallic microcavities in the THz range. I will discuss recent developments concerning new laser design approaches based on two and four quantum well structures together with results of sub-THz laser emission (0.75-1.4 THz) obtained by magnetically assisted gain in THz QC lasers. The optical resonator plays a key role in this class of lasers: the most widely adopted waveguide configuration uses metals as cladding layers. In the far-infrared the large negative dielectric constant of the metals enables the fabrication of THz QC lasers using sub-wavelength cavities with low modal volumes that borrow their concepts from conventional electronics. Recent results about this topic will be discussed. We used the same kind of microcavity resonator to access strong light-matter coupling regime in the THz range with intersubband transitions in quantum wells. I will report about our groups’ recent results on this topic including observation of strong light-matter coupling at room temperature at 4 THz.
Date: Mon, 22.11.2010
Time: 17:30
Duration: 60 min
Location:Universität Wien, Ernst-Mach-Hörsaal, Boltzmanngasse 5, 2nd floor, 1090 Wien
Contact:Prof. Karl Unterrainer

Acoustic Black Holes
Speaker:Massimiliano Rinaldi (Université de Genève)
Abstract: In 1981 a seminal paper by W. Unruh showed that it is possible to generate thermal emission in a superfluid, which has the same characteristics of the Hawking radiation emitted by astrophysical black holes. This analogy opened up the possibility to observe the Hawking radiation in a laboratory, in a variety of condensed matter systems. In recent years, this possibility has become a feasible reality, boosting the interest in the so-called analogue models of gravity. In this talk, I will first review the fundamentals of Hawking radiation in both astrophysical and condensed matter systems, focussing in particular on Bose-Einstein condensates. Then I will discuss some recent developments and future perspectives of this fascinating analogy. Schedule Overview
Date: Tue, 23.11.2010
Time: 12:30
Duration: 60 min
Location:TU Wien ( Wiedner Hauptstr. 8-10, yellow area, 10th floor, seminar room E136 )
Contact:Niklas Johansson

Stellar Equilibrium and Collapse
Speaker:Bettina Wutzl (Univ. Wien) (Fakultät für Physik)
Abstract:im Rahmen des Seminars für Mathematische Physik
Date: Tue, 23.11.2010
Time: 14:15
Duration: 60 min
Location:Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock, 1090 Wien
Contact:J. Yngvason

Magnetic order in the ultrathin iron film on the Ir(001) surface
Speaker:Dr. Frantisek Máca (Institute of Physics ASCR, Prague/CZ)
Abstract:We present detailed ab initio study of structural and magnetic stability of a Fe monolayer on the fcc (001) surface of iridium. The Fe monolayer has a strong tendency to order antiferromagnetically for the true relaxed geometry [1]. The ferromagnetism is stabilized by the increased Fe-Ir layer spacing. The present study centers around the evaluation of pair exchange interactions between Fe atoms in the Fe overlayer as a function of adsorbate coverage which allows for a detailed understanding of the antiferromagnetism of a Fe/Ir(001) overlayer. Our calculations indicate that the nature of the true ground state could be more complex and display a spin spiral like rather than a c(2x2)-antiferromagnetic order. We compare the influence of two adsorbate species, H and O, on the magnetic ground state. We found that the adsorption of oxygen (contrary to the H) lowers the stability of antiferromagnetic order and prefers ferromagnetic ground state. The scanning tunelling spectroscopy shows a surface state, its energy position varied with iron coverage. We present how the magnetic order and the iron coverage influence the surface state appearence. A comparison with recent experimental data will be also given. [1] J. Kudrnovský, F. Máca, I. Turek, and J. Redinger, Phys. Rev. B 80, 064405 (2009).
Date: Tue, 23.11.2010
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. Josef Redinger

Lyapunov spectra for alpha-Farey and alpha-Lueroth systems
Speaker:Dr. Sara Munday (St. Andrews University)
Date: Tue, 23.11.2010
Time: 16:00
Location:ESI Schrödinger Lecture Hall
Contact:secr@esi.ac.at

Membrane Paradigm in f(R) gravity
Speaker:Sudipta Sarkar (IUCAA, Pune)
Abstract:The membrane paradigm is the remarkable view that, to an external observer, a black hole appears to behave exactly like a dynamical fluid membrane, obeying pre-relativistic equations. We extend the existing membrane formalism for General relativity to black holes in any general f(R)-theory of gravity and derive the stress tensor and various transport coefficients of the membrane fluid. The membrane turns out to behave like a non-Newtonian fluid except for the case of General Relativity. We also derive dynamical equations describing the fluid membrane. This result establishes the general analogy of the properties of black hole horizon with fluid mechanics beyond General Relativity to any general f(R) gravity theory.
Date: Wed, 24.11.2010
Time: 14:15
Duration: 60 min
Location:SEM 136, Institute for Theoretical Physics, Vienna University of Technology
Contact:Daniel Grumiller

Confrontation of tau-decay and electron positron hadrons data with QCD
Speaker:Karl Schilcher (Univ. Mainz)
Abstract:im Rahmen des Teilchenphysikseminars
Date: Thu, 25.11.2010
Time: 14:15
Duration: 60 min
Location:Fakultät für Physik, Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock, 1090 Wien
Contact:A. Hoang

Driven stochastic processes with metastable states: Fokker-Planck versus master equations
Speaker:Peter Talkner (Augsburg)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Fri, 26.11.2010
Time: 10:05
Duration: 45 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Position zur Rolle der Intuition
Speaker:Reinhold Bertlmann (Univ. Wien) und Susanne Granzer (Univ. Wien) (Arge )
Abstract:Symposium
Date: Fri, 26.11.2010
Time: 10:45
Duration: 45 min
Location:Akademie der Bildenden Künste Wien, Raum R1, Schillerplatz 3, 1010 Wien
Contact:R.A. Bertlmann

Complex stochastic dynamics in spin glasses and optimization problems
Speaker:Federico Ricci-Tersenghi (Roma)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Fri, 26.11.2010
Time: 11:20
Duration: 45 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Model for gravity in the IR
Speaker:Dr. Daniel Grumiller (TU Wien) (Fakultät für Physik)
Abstract:Vortrag
Date: Fri, 26.11.2010
Time: 13:30
Duration: 60 min
Location:Währinger Strasse 17, 1. Stock, Zimmer 114
Contact:P.C. Aichelburg

IR Assisted Photoionization of Atoms by Attosecond XUV Pulses
Speaker:Xiao-Min Tong, University of Tsukuba (ADLIS Seminar)
Date: Fri, 26.11.2010
Time: 14:00
Duration: 60 min
Location:SR Photonik: Institut f. Photonik, Gusshausstraße 27, 1040 Wien / Erdgeschoß, CBEG02
Contact:Heike Höller, SFB ADLIS Sekretariat, 58801 13625

Genuine Entanglement in Complex Systems
Speaker:Marcus Huber (Univ.Wien)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Fri, 26.11.2010
Time: 15:00
Duration: 20 min
Location:Fakultät für Physik, Christian-Doppler Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Entropies for Complex Systems
Speaker:Stefan Thurner (Vienna)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Fri, 26.11.2010
Time: 15:25
Duration: 45 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Complexity in Evolutionary Processes
Speaker:Peter Schuster (Vienna)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Fri, 26.11.2010
Time: 16:45
Duration: 45 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

The proton spin puzzle: Where are we today?
Speaker:Steven Bass (Institute for Theoretical Physics, Universität Innsbruck)
Abstract:The proton spin puzzle has challenged our understanding of QCD for the last 20 years. New measurements of polarized glue, valence and sea quark polarization, including strange quark polarization, are available. What is new and exciting in the data, and what might this tell us about the structure of the proton? The proton spin puzzle seems to be telling us about the interplay of valence quarks with chiral dynamics and the complex vacuum structure of QCD.
Date: Fri, 26.11.2010
Time: 17:00
Duration: 60 min
Location:SMI, Seminar room, Boltzmanngasse 3, 1090 Wien, Room 2.08
Contact:Roland Gsell

Almost Linear Systems - A null-model for genetic regulatory networks
Speaker:Rudolf Hanel (Vienna)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Fri, 26.11.2010
Time: 17:35
Duration: 20 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Reaction kinetics in the presence of synthetic velocity field
Speaker:Tomàs Lucivjanský (Kosice)
Abstract:7th Vienna Central European Seminar an Particle Physics and Quantum Field Theory
Date: Fri, 26.11.2010
Time: 18:00
Duration: 20 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Complex behavior in chaotically quantized field theories
Speaker:Christian Beck (London)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Fri, 26.11.2010
Time: 18:25
Duration: 45 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Complex Networks
Speaker:Frank Schweitzer (ETH Zürich)
Abstract:im Rahmen des "7th Vienna Central European Seminar"
Date: Fri, 26.11.2010
Time: 19:30
Duration: 60 min
Location:Fakultät für Physik, Christian-Doppler Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Dynamics of interactions in a large communication network
Speaker:Janos Kertesz (Budapest)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Sat, 27.11.2010
Time: 10:00
Duration: 45 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Multi-scale Modularity in Complex Networks
Speaker:Renaud Lambiotte (London)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Sat, 27.11.2010
Time: 11:20
Duration: 45 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Complex human mobility dynamics on a network
Speaker:Michael Szell (Vienna)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Sat, 27.11.2010
Time: 15:00
Duration: 20 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Local and nonlocal information in a traffic network: how important is the horizon?
Speaker:Giovanni Petri (London)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Sat, 27.11.2010
Time: 15:25
Duration: 20 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Linguistic-based analysis of Wikipedia: a complex systems approach
Speaker:Taha Yasseri (Budapest)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Sat, 27.11.2010
Time: 15:50
Duration: 20 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Complex stochastic dynamics in the modeling of living systems
Speaker:Annick Lesne (Paris)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Sat, 27.11.2010
Time: 16:45
Duration: 45 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Modeling collective emotions: a stochastic approach based on Brownian agents
Speaker:Frank Schweitzer (Zürich)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Sat, 27.11.2010
Time: 17:35
Duration: 45 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Noise and Society: A directed Random Walk towards an Elementary Theory of Social Systems
Speaker:Dirk Helbing (Zürich)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Sun, 28.11.2010
Time: 10:00
Duration: 45 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Topologically biased random walk with application for community finding in networks
Speaker:Vinko Zlatic (Zagreb)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Sun, 28.11.2010
Time: 11:20
Duration: 20 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel

Maximal Entropy Random Walk
Speaker:Zdzislaw Burda (Krakow)
Abstract:7th Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Date: Sun, 28.11.2010
Time: 11:45
Duration: 45 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 3. Stock, 1090 Wien
Contact:H. Hüffel