Universality of phonon-roton spectrum in liquids and superfluidity of He II

Based on numerous experimental data on inelastic neutron and X-ray scattering in liquids, we assert that the phonon-roton spectrum of elementary excitations, predicted by Landau for superfluid helium, is a universal property of the liquid state. We show that the existence of the roton minimum in the...

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Bibliographic Details
Published in:arXiv.org 2014-07
Main Authors: Bobrov, V B, Trigger, S A, Litinski, D I
Format: Article
Language:English
Subjects:
Elementary excitations
Energy spectra
Excitation spectra
Fluids
Helium
Inelastic scattering
Liquids
Phonons
Short range order
Superfluidity
X-ray scattering
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Summary:Based on numerous experimental data on inelastic neutron and X-ray scattering in liquids, we assert that the phonon-roton spectrum of elementary excitations, predicted by Landau for superfluid helium, is a universal property of the liquid state. We show that the existence of the roton minimum in the spectrum of collective excitations is caused by the short-range order in liquids. Using the superfluidity criterion, we assume that one more branch of collective excitations should exist in He II, whose energy spectrum differs from the phonon-roton spectrum.
ISSN:2331-8422