The Possibility of Existence of an Energy Gap in the One-Particle Excitation Spectrum of He II

2009/06/03 by I. M. Yurin, Yurin, I. M., S. A. Trigger +1
Physics and Astronomy · #Atomic and Subatomic Physics Research #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #Quantum Gases (cond-mat.quant-gas) #Quantum, superfluid, helium dynamics #Superconductivity (cond-mat.supr-con) #cond-mat.quant-gas #cond-mat.supr-con

paper · pdf · doi:10.48550/arxiv.0906.0755

14 pages, 2 figures

openalex publication_date 2009/06/03 · arxiv created 2009/06/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

Possibility for coexistence of a phonon and one-particle spectra in ⁴He at all temperatures including temperatures below the λ - point is shown. An approach developed to consider the problem of the weakly imperfect Bose gas results in the existence of a gap in the one-particle (one-atom) excitation spectrum below the transition point. Thus, the microscopic model of He II turns out to differ both from the model initially suggested by Landau and from the Bogolyubov model accepted at present. Analysis of the experimental data obtained by measuring enthalpy and the part of helium atoms condensed in the state with the momentum p=0 enabled to estimate the size of the gap. It turned out to be approximately equal to 0.31 K at zero temperature.

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