Superfluid 4He dynamics beyond quasiparticle excitations

Abstract

The dynamics of superfluid 4He at and above the Landau quasiparticle regime is investigated by high precision inelastic neutron scattering measurements of the dynamic structure factor. A highly structured response is observed above the familiar phonon-maxon-roton spectrum, characterized by sharp thresholds for phonon-phonon, maxon-roton and roton-roton coupling processes. The experimental dynamic structure factor is compared to the calculation of the same physical quantity by a Dynamic Many-body theory including three-phonon processes self-consistently. The theory is found to provide a quantitative description of the dynamics of the correlated bosons for energies up to about three times that of the Landau quasiparticles.

arXiv comment5 pages, 3 figures

References in corpus (5)

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• One-dimensional liquid ${}^4$He: dynamical properties beyond Luttinger liquid theory
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• Dynamical structure factor of one-dimensional hard rods
• Microscopic dynamics of superfluid ${}^4$He: a comprehensive study by inelastic neutron scattering
• The Multi-component Correlated Basis Function Method and its Application to Multilayered Dipolar Bose Gases
• Variational and parquet-diagram calculations for neutron matter. IV. Spin-orbit interactions and linear response
• Maxon and roton measurements in nanoconfined ${}^4$He
• Transport and Phonon Damping in ${}^4$He
• Breakdown of sound in superfluid helium
• Momentum distribution of liquid 4He across the normal-superfluid phase transition