High-Resolution Measurements of Rotons in 4He

Andersen, K. H.; Bossy, J.; Cook, J. C.; Randl, O. G.; Ragazzoni, J.

doi:10.1103/PhysRevLett.77.4043

High-Resolution Measurements of Rotons in ⁴He

Journal Article · Fri Nov 01 04:00:00 EST 1996 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.77.4043· OSTI ID:389394

Andersen, K. H. ^[1]; Bossy, J. ^[1]; Cook, J. C. ^[1]; Randl, O. G. ^[1]; Ragazzoni, J. ^[2]

Institut Laue-Langevin, Grenoble (France)
Institut Laue-Langevin, B.P. 156, 38042 Grenoble Cedex 9 (France)

A direct measurement of the roton line shape in superfluid ⁴He down to T=0.8 K has been possible using neutron backscattering with a measured energy resolution of less than 1μeV. These results constitute a significant improvement on the previous best determination and extend the measured range of roton linewidth and energy shift by an order of magnitude. The temperature dependence of the measured linewidths is found to be in excellent agreement with calculations based on the 4-phonon decay process. The roton energy, however, is found to vary significantly more slowly with temperature than expected from the same theory. The origin of this discrepancy is not yet understood.

OSTI ID:: 389394

Journal Information:: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 19 Vol. 77; ISSN 0031-9007

Publisher:: American Physical Society (APS)

Country of Publication:: United States

Language:: English

References (7)

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Pseudopotential theory of interacting roton pairs in superfluid He 4 Bedell, K.; Pines, D.; Zawadowski, A. Physical Review B, Vol. 29, Issue 1 https://doi.org/10.1103/PhysRevB.29.102	journal	January 1984
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Collective excitations in liquid ⁴ He. II. Analysis and comparison with theory Andersen, K. H.; Stirling, W. G. Journal of Physics: Condensed Matter, Vol. 6, Issue 30 https://doi.org/10.1088/0953-8984/6/30/004	journal	July 1994
Statistical mechanics of strongly correlated Bose quantum fluids Clements, B. E.; Krotscheck, E.; Smith, J. A. Physical Review B, Vol. 47, Issue 9 https://doi.org/10.1103/PhysRevB.47.5239	journal	March 1993

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Related Subjects

66 PHYSICS
BACKSCATTERING
HELIUM 4
NEUTRON DIFFRACTION
ROTONS
SUPERFLUIDITY
TEMPERATURE DEPENDENCE

High-Resolution Measurements of Rotons in 4He

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High-Resolution Measurements of Rotons in ⁴He