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

General Physics and Astronomy

Electronic version(s)

https://doi.org/10.48550/arXiv.1812.03064 (Access: Open)
https://doi.org/10.1103/PhysRevLett.122.163601 (Access: Closed)