The Momentum Distribution of Liquid $^4$He
Abstract
We report high-resolution neutron Compton scattering measurements of liquid He under saturated vapor pressure. There is excellent agreement between the observed scattering and ab initio predictions of its lineshape. Quantum Monte Carlo calculations predict that the Bose condensate fraction is zero in the normal fluid, builds up rapidly just below the superfluid transition temperature, and reaches a value of approximately below 1 K. We also used model fit functions to obtain from the scattering data empirical estimates for the average atomic kinetic energy and Bose condensate fraction. These quantities are also in excellent agreement with ab initio calculations. The convergence between the scattering data and Quantum Monte Carlo calculations is strong evidence for a Bose broken symmetry in superfluid He.
Keywords
Cite
@article{arxiv.1703.03018,
title = {The Momentum Distribution of Liquid $^4$He},
author = {Timothy R. Prisk and Matthew S. Bryan and Paul. E. Sokol and Garrett E. Granroth and Saverio Moroni and Massimo Boninsegni},
journal= {arXiv preprint arXiv:1703.03018},
year = {2017}
}
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11 figures