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Updated: Mar 3, 2026
11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
9.1K
Observation of dynamic atom-atom correlation in liquid helium in real space
W Dmowski1,2, S O Diallo3, K Lokshin1,2
1Shull Wollan Center-Joint-Institute for Neutron Sciences, Oak Ridge National Laboratory and University of Tennessee, Oak Ridge, Tennessee 37831, USA.
Nature Communications
|May 5, 2017
Summary
Researchers used neutron dynamic pair-density function (DPDF) analysis to study superfluid 4He. They found distinct atomic environments and evidence of atomic tunneling in the Bose-Einstein condensate, offering new insights into superfluid dynamics.
Area of Science:
- Condensed Matter Physics
- Quantum Fluids
- Low-Temperature Physics
Background:
- Liquid 4He exhibits superfluidity below 2.17 K, a phenomenon extensively studied but with microscopic details remaining unclear.
- Understanding dynamic atom-atom correlations in the superfluid state is crucial for a complete picture of this quantum phenomenon.
Purpose of the Study:
- To investigate the microscopic environment and dynamic correlations of 4He atoms in the superfluid state.
- To elucidate the role of Bose-Einstein condensate in the superfluid properties of 4He.
- To reveal previously unrecognized characteristics of atomic dynamics in superfluid 4He.
Main Methods:
- Utilized neutron dynamic pair-density function (DPDF) analysis, a technique for probing atomic correlations in real space.
- Analyzed the structure and interatomic distances of 4He atoms in both condensed and uncondensed states.
Main Results:
- Identified that 4He atoms within the Bose-Einstein condensate possess a distinct environment compared to uncondensed atoms.
- Observed that the interatomic distance for condensed atoms is approximately 10% larger than the average, while overall structure remains largely unchanged across the superfluid transition.
- Detected a DPDF peak at 2.3 Å, absent in snapshot pair-density functions, interpreted as evidence of atomic tunneling.
Conclusions:
- The study provides a real-space visualization of dynamic atom-atom correlations in superfluid 4He.
- Findings reveal novel characteristics of atomic dynamics, including atomic tunneling, within the superfluid state.
- The results necessitate a re-examination of the fundamental understanding of superfluidity in 4He.
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