Berlin 2014 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 32: Poster: Quantum gases, ultracold atoms and molecules

Q 32.14: Poster

Mittwoch, 19. März 2014, 16:30–18:30, Spree-Palais

Nonthermal Fixed Points and Superfluid Turbulence in Ultracold Bose GasesSebastian Erne1,2, •Markus Karl1,2, Steven Mathey1,2, Boris Nowak1,2, Andreas Samberg1,2, Jan Schole1,2, Carlo Ewerz1,2, and Thomas Gasenzer1,21Institut für Theoretische Physik, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg — 2ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt, Germany

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 and quantum-field theoretic methods based on effective-action techniques. These give information about possible universal scaling behaviour. The connection of this scaling with the appearance of topological excitations such as solitons and vortices in one-component gases and domain walls and spin textures in multi-component systems is discussed. In addition, this results are also discussed from the point of view of holographic superfluids. 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 non-thermal fixed points and superfluid turbulence in experiment without the necessity of detecting solitons and vortices in situ.

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