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Title: Observation of dynamic atom-atom correlation in liquid helium in real space

Abstract

Liquid 4He becomes superfluid and flows without resistance below temperature 2.17 K. Superfluidity has been a subject of intense studies and notable advances were made in elucidating the phenomenon by experiment and theory. Nevertheless, details of the microscopic state, including dynamic atom–atom correlations in the superfluid state, are not fully understood. Here using a technique of neutron dynamic pair-density function (DPDF) analysis we show that 4He atoms in the Bose–Einstein condensate have environment significantly different from uncondensed atoms, with the interatomic distance larger than the average by about 10%, whereas the average structure changes little through the superfluid transition. DPDF peak not seen in the snap-shot pair-density function is found at 2.3 Å, and is interpreted in terms of atomic tunnelling. The real space picture of dynamic atom–atom correlations presented here reveal characteristics of atomic dynamics not recognized so far, compelling yet another look at the phenomenon.

Authors:
 [1];  [2];  [1]; ORCiD logo [2];  [3];  [3];  [4]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Shull Wollan Center-Joint Inst. for Neutron Sciences; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Material Science and Engineering
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Univ. Politecnica de Catalunya, Barcelona (Spain). Dept. de Fisica
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Shull Wollan Center-Joint Inst. for Neutron Sciences; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Material Science and Engineering; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); MINECO (Spain)
OSTI Identifier:
1355884
Grant/Contract Number:
AC05-00OR22725; FIS2014-56257-C2-1-P
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 8; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; helium; superfluidity; Bose–Einstein condensates; Quantum fluids and solids

Citation Formats

Dmowski, W., Diallo, S. O., Lokshin, K., Ehlers, G., Ferré, G., Boronat, J., and Egami, T. Observation of dynamic atom-atom correlation in liquid helium in real space. United States: N. p., 2017. Web. doi:10.1038/ncomms15294.
Dmowski, W., Diallo, S. O., Lokshin, K., Ehlers, G., Ferré, G., Boronat, J., & Egami, T. Observation of dynamic atom-atom correlation in liquid helium in real space. United States. doi:10.1038/ncomms15294.
Dmowski, W., Diallo, S. O., Lokshin, K., Ehlers, G., Ferré, G., Boronat, J., and Egami, T. 2017. "Observation of dynamic atom-atom correlation in liquid helium in real space". United States. doi:10.1038/ncomms15294. https://www.osti.gov/servlets/purl/1355884.
@article{osti_1355884,
title = {Observation of dynamic atom-atom correlation in liquid helium in real space},
author = {Dmowski, W. and Diallo, S. O. and Lokshin, K. and Ehlers, G. and Ferré, G. and Boronat, J. and Egami, T.},
abstractNote = {Liquid 4He becomes superfluid and flows without resistance below temperature 2.17 K. Superfluidity has been a subject of intense studies and notable advances were made in elucidating the phenomenon by experiment and theory. Nevertheless, details of the microscopic state, including dynamic atom–atom correlations in the superfluid state, are not fully understood. Here using a technique of neutron dynamic pair-density function (DPDF) analysis we show that 4He atoms in the Bose–Einstein condensate have environment significantly different from uncondensed atoms, with the interatomic distance larger than the average by about 10%, whereas the average structure changes little through the superfluid transition. DPDF peak not seen in the snap-shot pair-density function is found at 2.3 Å, and is interpreted in terms of atomic tunnelling. The real space picture of dynamic atom–atom correlations presented here reveal characteristics of atomic dynamics not recognized so far, compelling yet another look at the phenomenon.},
doi = {10.1038/ncomms15294},
journal = {Nature Communications},
number = ,
volume = 8,
place = {United States},
year = 2017,
month = 5
}

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