Hannover 2016 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 27: Poster: Quantum Optics and Photonics II
Q 27.1: Poster
Dienstag, 1. März 2016, 16:30–19:00, Empore Lichthof
Nonthermal Fixed Points and Superfluid Turbulence in Ultracold Bose Gases — Halil Cakir1, Stefanie Czischek1, •Markus Karl1,2, Eike Nicklas1, Thomas Gasenzer1,2, and Markus K. Oberthaler1 — 1Kirchhoff-Institut für Physik, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg — 2Institut für Theoretische Physik, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg
Ultracold quantum gases provide various means to probe universal many-body dynamics far from equilibrium. Here, we focus on the non-linear dynamical evolution induced in an ultra cold Bose gas by a sudden initial parameter quench. Considering one- or multi-component (spin) systems, various types of spatial and wavenumber- space patterns emerge, being characterized by universal scaling functions associated with non-thermal fixed points. Such fixed points can be observed in existing experiments and are closely related to quantum turbulence usually discussed in systems of more than one spatial dimension. While these situations are associated with quenches to a symmetry-broken state, quenches within the symmetric phase offer a way to probe the properties of universal dynamics similar to those near a quantum critical point in equilibrium. Scaling properties have been found which indicate the importance of pre-thermalisation temperatures long before dephasing has occurred in the nearly gapless system. We discuss the theoretical results in the light of and illustrated by recent experimental measurements.