Hannover 2016 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

Q: Fachverband Quantenoptik und Photonik

Q 17: Quantum Gases: Bosons I

Q 17.6: Talk

Tuesday, March 1, 2016, 12:30–12:45, e001

Evidence of Non-Thermal Fixed Points in one-dimensional Bose gases — •Sebastian Erne^1,2,4, Robert Bücker⁴, Wolfgang Rohringer⁴, Thomas Gasenzer^1,2,3, and Jörg Schmiedmayer⁴ — ¹Institut für Theoretische Physik, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany — ²ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt, Germany — ³Kirchhoff-Institut für Physik, INF 227, 69120 Heidelberg, Germany — ⁴Vienna Center for Quantum Science and Technology (VCQ), Atominstitut, TU Wien, Vienna, Austria

This work investigates the rapid cooling quench over the dimensional- and quasicondensate-crossover. Analyzing experiments performed at the Atominstitut, we study the relaxation of such a far-from equilibrium system. The early stage of condensate formation is dominated by solitonic excitations, leading to a characteristic momentum distribution in agreement with a model of randomly distributed defects. The number of solitons increases with the quenchrate giving rise to an incompressible condensate. The isolated system follows a self-similar evolution governed by a universal time-independent nonthermal fixed point distribution. The dynamic universality classes of these nonequilibrium attractor solutions are relevant for a wide variety of physical systems ranging from relativistic high-energy physics to cold quantum gases. At later times of the evolution the system fully equilibrates leading to deviations from the self-similar evolution. Our results show a new way of condensation in far from equilibrium 1d Bose gases.