Observation of Atom Number Fluctuations in a Bose-Einstein Condensate

authored by: M. A. Kristensen, M. B. Christensen, M. Gajdacz, M. Iglicki, K. Pawłowski, Carsten Klempt, J. F. Sherson, K. Rzazewski, A. J. Hilliard, J. J. Arlt
Abstract: Fluctuations are a key property of both classical and quantum systems. While the fluctuations are well understood for many quantum systems at zero temperature, the case of an interacting quantum system at finite temperature still poses numerous challenges. Despite intense theoretical investigations of atom number fluctuations in Bose-Einstein condensates, their amplitude in experimentally relevant interacting systems is still not fully understood. Moreover, technical limitations have prevented their experimental investigation to date. Here we report the observation of these fluctuations. Our experiments are based on a stabilization technique, which allows for the preparation of ultracold thermal clouds at the shot noise level, thereby eliminating numerous technical noise sources. Furthermore, we make use of the correlations established by the evaporative cooling process to precisely determine the fluctuations and the sample temperature. This allows us to observe a telltale signature: the sudden increase in fluctuations of the condensate atom number close to the critical temperature.
Organisation(s): QuantumFrontiers
Institute of Quantum Optics
CRC 1227 Designed Quantum States of Matter (DQ-mat)
External Organisation(s): Aarhus University
Center for Theoretical Physics of the Polish Academy of Sciences
University of Warsaw
Type: Article
Journal: Physical Review Letters
Volume: 122
No. of pages: 6
ISSN: 0031-9007
Publication date: 26.04.2019
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Physics and Astronomy(all)
Electronic version(s): https://doi.org/10.48550/arXiv.1812.03064 (Access: Open)
https://doi.org/10.1103/PhysRevLett.122.163601 (Access: Closed)

BibTeX

@article{dd4228fd93f348f883850a1c9efebc54,
title = "Observation of Atom Number Fluctuations in a Bose-Einstein Condensate",
abstract = "Fluctuations are a key property of both classical and quantum systems. While the fluctuations are well understood for many quantum systems at zero temperature, the case of an interacting quantum system at finite temperature still poses numerous challenges. Despite intense theoretical investigations of atom number fluctuations in Bose-Einstein condensates, their amplitude in experimentally relevant interacting systems is still not fully understood. Moreover, technical limitations have prevented their experimental investigation to date. Here we report the observation of these fluctuations. Our experiments are based on a stabilization technique, which allows for the preparation of ultracold thermal clouds at the shot noise level, thereby eliminating numerous technical noise sources. Furthermore, we make use of the correlations established by the evaporative cooling process to precisely determine the fluctuations and the sample temperature. This allows us to observe a telltale signature: the sudden increase in fluctuations of the condensate atom number close to the critical temperature.",
author = "Kristensen, {M. A.} and Christensen, {M. B.} and M. Gajdacz and M. Iglicki and K. Paw{\l}owski and Carsten Klempt and Sherson, {J. F.} and K. Rzazewski and Hilliard, {A. J.} and Arlt, {J. J.}",
note = "Funding information: M. A. K., M. B. C., M. G., J. F. S., A. J. H., and J. J. A. acknowledge support from the Villum Foundation, the Carlsberg Foundation, and the Danish Council for Independent Research. This work was supported by the (Polish) National Science Center Grants No. 2014/13/D/ST2/01883 (K. P.) and No. 2015/19/B/ST2/02820 (K. R. and M. I.). C. K. acknowledges support by the Deutsche Forschungsgemeinschaft (DFG) through Grant No. CRC 1227 (DQ-mat), project B01.",
year = "2019",
month = apr,
day = "26",
doi = "10.48550/arXiv.1812.03064",
language = "English",
volume = "122",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "16",
}