Dresden 2017 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 11: Critical phenomena
DY 11.1: Vortrag
Montag, 20. März 2017, 15:30–15:45, HÜL 186
Temperatures are not useful to characterise bright-soliton experiments for ultra-cold atoms — •Christoph Weiss1, Simon Gardiner1, and Bettina Gertjerenken2 — 1Joint Quantum Centre (JQC) Durham-Newcastle, Department of Physics, Durham University, UK — 2Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA 01003-4515, USA
Contrary to many other translationally invariant one-dimensional models, the low-temperature phase for an attractively interacting one-dimensional Bose-gas (a quantum bright soliton) is stable against thermal fluctuations [1,2]. However, treating the thermal properties of quantum bright solitons within the canonical ensemble leads to anomalous fluctuations of the total energy that indicate that canonical and micro-canonical ensembles are not equivalent. State-of-the-art experiments are best described by the micro-canonical ensemble, within which we predict a co-existence between single atoms and solitons even in the thermodynamic limit - contrary to strong predictions based on both the Landau hypothesis and the canonical ensemble. This questions the use of temperatures to describe state-of-the-art bright soliton experiments that currently load Bose-Einstein condensates into quasi-one-dimensional wave guides without adding contact to a heat bath. [3]
[1] C. Weiss, arXiv:1610.09070
[2] C. Herzog, M. Olshanii, and Y. Castin, Comptes Rendus Physique 15, 285 (2014), arXiv:1311.3857.
[3] C. Weiss, S. A. Gardiner, B. Gertjerenken, arXiv:1610.09074