Observation of the Berezinskii-Kosterlitz-Thouless Transition in a Two-Dimensional Bose Gas via Matter-Wave Interferometry

authored by: S. Sunami, V. P. Singh, D. Garrick, A. Beregi, A. J. Barker, K. Luksch, E. Bentine, L. Mathey, C. J. Foot
Abstract: We probe local phase fluctuations of trapped two-dimensional Bose gases using matter-wave interferometry. This enables us to measure the phase correlation function, which changes from an algebraic to an exponential decay when the system crosses the Berezinskii-Kosterlitz-Thouless (BKT) transition. We determine the temperature dependence of the BKT exponent η and find the critical value ηc=0.17(3) for our trapped system. Furthermore, we measure the local vortex density as a function of the local phase-space density, which shows a scale-invariant behavior across the transition. Our experimental investigation is supported by Monte Carlo simulations and provides a comprehensive understanding of the BKT transition in a trapped system.
Organisation(s): QuantumFrontiers
Institute of Theoretical Physics
External Organisation(s): University of Oxford
Universität Hamburg
Type: Article
Journal: Physical review letters
Volume: 128
ISSN: 0031-9007
Publication date: 22.06.2022
Publication status: Published
Peer reviewed: Yes
Electronic version(s): https://doi.org/10.1103/PhysRevLett.128.250402 (Access: Closed)

BibTeX

@article{d34ad47d06da4b44be16c7cfc24ca44e,
title = "Observation of the Berezinskii-Kosterlitz-Thouless Transition in a Two-Dimensional Bose Gas via Matter-Wave Interferometry",
abstract = "We probe local phase fluctuations of trapped two-dimensional Bose gases using matter-wave interferometry. This enables us to measure the phase correlation function, which changes from an algebraic to an exponential decay when the system crosses the Berezinskii-Kosterlitz-Thouless (BKT) transition. We determine the temperature dependence of the BKT exponent η and find the critical value ηc=0.17(3) for our trapped system. Furthermore, we measure the local vortex density as a function of the local phase-space density, which shows a scale-invariant behavior across the transition. Our experimental investigation is supported by Monte Carlo simulations and provides a comprehensive understanding of the BKT transition in a trapped system.",
author = "S. Sunami and Singh, {V. P.} and D. Garrick and A. Beregi and Barker, {A. J.} and K. Luksch and E. Bentine and L. Mathey and Foot, {C. J.}",
note = "Funding Information: We acknowledge discussions with Junichi Okamoto, Beilei Zhu, and Zoran Hadzibabic. This work was supported by the EPSRC Grant Reference EP/S013105/1. S. S. acknowledges the Murata scholarship foundation, Ezoe Foundation, Daishin Foundation, and St Hilda{\textquoteright}s College for financial support. D. G., A. B., A. J. B., and K. L. thank the EPSRC for doctoral training funding. L. M. acknowledges funding by the Deutsche Forschungsgemeinschaft (DFG) in the framework of SFB 925—project ID 170620586 and the Excellence Cluster “Advanced Imaging of Matter”—EXC 2056—project ID 390715994. V. P. S. acknowledges funding by the Cluster of Excellence “QuantumFrontiers”—EXC 2123—project ID 390837967.",
year = "2022",
month = jun,
day = "22",
doi = "10.1103/PhysRevLett.128.250402",
language = "English",
volume = "128",
journal = "Physical review letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "25",
}