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Calendar of Physics Talks Vienna
| Correlation functions of 1D Bose gases: from weak to strong interaction - 2nd part |
| Speaker: | Dr Isabelle Bouchoule (Institut d'Optique, Palaiseau, France) |
| Abstract: | Among the systems of many-body physics, one-dimensional Bose gases attract a lot of interest since a deep understanding of the physics is possible and fascinating behaviors occur such as the fermionisation of the gas for strong interactions. In the past few years, many cold atoms experiments investigated such systems and several important results were reported both in weak interaction regime and in the strong interaction regime.
In this lecture, we will give an overview of the properties of 1D Bose gases. We will identify the different asymptotic regimes. In each regime, we will discuss correlation functions, which are quantities that describe the gas properties and which are explored experimentally. A special focus will be put on the so-called "quasi-condensate regime": after introducing the Bogoliubov theory, we will show how it enables the calculation of correlation function.
Results of experiments will be commented. |
| Date: | Mon, 27.06.2011 |
| Time: | 14:00 |
| Duration: | 90 min |
| Location: | Seminar room, Institute of Atomic and Subatomic Physics, Stadionallee 2, 1020 Vienna |
| Contact: | Dr Thorsten Schumm |
| Stochastic Thermodynamics |
| Speaker: | Udo Seifert (II. Institut für Theoretische Physik, Universität Stuttgart) |
| Abstract: | In this talk, I will give an introduction into the emerging field of stochastic thermodynamics and illustrate its main concepts with recent experimental data.
Stochastic thermodynamics provides a framework for describing small systems embedded in a heat bath and externally driven to non-equilibrium. Examples are colloidal particles in time-dependent optical traps, single biomolecules manipulated by optical tweezers or AFM tips, and motor proteins driven by ATP excess. The notions of classical thermodynamics like applied work, exchanged heat and total entropy production valid there on the ensemble level can now be consistently identified and measured on the level of an individual stochastic trajectory. Moreover, exact results that refine the second law like the Jarzynski relation and fluctuation theorems for entropy production can be proven. Key elements of this framework like a stochastic entropy can also be applied to quantum systems as experiments on an optically driven defect center in diamond will show. Finally, using these concept, the efficiency of nanoscopic machines like molecular motors can be determined and their performance be optimized.
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| Date: | Mon, 27.06.2011 |
| Time: | 17:30 |
| Location: | Universität Wien, Lise Meitner Hörsaal, Strudlhofg. 4, 1090 Wien |
| Contact: | J. Schmiedmayer |
| Pumpschwingungen bei Einseilumlaufbahnen |
| Speaker: | Harald Nicolussi (Technische Universität Wien, Institut für Angewandte Physik) |
| Abstract: | Einseilumlaufbahnen sind effiziente, sichere und im Gebirge die wohl kostengünstigsten Transportmittel um viele Personen (mehrere tausend pro Stunde) zu befördern. Bei manchen Seilbahnen kommt es im stationären Zustand (das Seil bewegt sich mit konstanter Geschwindigkeit aus der Antriebsstation) zu Schwingungserscheinungen mit großen Durchhangsänderungen, mit bis zu einigen Metern Amplitude in der Feldmitte. Es treten meist Periodendauern von einigen Sekunden auf. Diese niederfrequente Schwingungsform wird Pumpen genannt.
Das Pumpen führt sowohl zu höherer Belastung der Seilbahn, als auch zu einem sehr unangenehmen Fahrgefühl bei den zu befördernden Personen. Das Pumpen tritt meist nur in einem engen Fahrgeschwindigkeitsbereich und bei einem bestimmten Belastungsfall auf.
Durch die rechnerische Analyse mehrerer bestehender Bahnen und Messungen ist es möglich Parameter zu finden, um die Schwingungen zu charakterisieren.
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| Date: | Tue, 28.06.2011 |
| 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. Martin Gröschl |
| Gauge theories with noncommutative extra dimensions |
| Speaker: | Athanasios Chatzistavrakidis (Univ. Bonn) |
| Abstract: | im Rahmen des Teilchenphysikseminars |
| Date: | Thu, 30.06.2011 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock, 1090 Wien |
| Contact: | H. Steinacker, H. Neufeld |
| The initial singularity of ultrastiff perfect fluid spacetimes without symmetries |
| Speaker: | J. Mark Heinzle (Univ. Wien) |
| Abstract: | im Rahmen des Literaturseminars |
| Date: | Thu, 30.06.2011 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Arbeitsgruppe: Gravitation, Währinger Strasse 17, Seminarraum A, 2. Stock |
| Contact: | R. Beig |
| Entropy rate of random walks on networks |
| Speaker: | Roberta Sinatra (Univ. of Catania) |
| Date: | Fri, 01.07.2011 |
| Time: | 14:30 |
| Duration: | 90 min |
| Location: | Medizinische Univ., Seminarraum 513, Bauteil 88, |
| Contact: | H. Hüffel, Stefan Thurner |
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