The lifetime of interacting ripplons on the surface of superfluid helium

• Published in: Journal of low temperature physics Vol. 92; no. 3-4; pp. 239 - 261
• Main Authors: JONES, R. C, WILLIAMS, A. J. E, VINEN, W. F, EWBANK, P. A
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01.08.1993
• Subjects: Boson degeneracy and superfluidity of 4he; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Condensed matter: structure, mechanical and thermal properties; EVEN-EVEN NUCLEI; Exact sciences and technology; HELIUM 4; HELIUM ISOTOPES; ISOTOPES; LIFETIME; LIGHT NUCLEI; NUCLEI; Physics; Quantum fluids and solids; liquid and solid helium; STABLE ISOTOPES; SUPERFLUIDITY; SURFACE PROPERTIES; TEMPERATURE RANGE 0000-0013 K; TEMPERATURE RANGE 665420 > Superfluidity > (1992-); Transport processes, second and other sounds, and thermal counterflow; kapitza resistance; TRAVELLING WAVES; Surfaces; Lifetime; Wave propagation; Helium 4; Ripplons; Superfluid
• ISSN: 0022-2291; 1573-7357
• DOI: 10.1007/BF00682340

Ripplons, or quantized surface waves, are known to exist on the surface of superfluid [sup 4]He. The authors follow the work of previous authors and describe these excitations by quantizing the classical expressions for the energy of such surface waves. The resulting quantum mechanical Hamiltonian consists of a term describing free ripplons, together with an additional term (cubic in the ripplon variables) which induces the mutual scattering of ripplons and has the effect of causing any one ripplon to have a finite lifetime. They present here a many body calculation which investigates the lifetimes of ripplons at a temperature T = 0 and the lifetimes of acoustic ripplons at a finite temperature. In these two limits their calculation agrees with separate calculations performed by previous authors carried out at the two limits; however their calculations readily allow a sensible interpolation between these limits. They report hitherto unsuspected divergences in the calculations at finite temperature and they comment on the relevance of such calculations to the results of recent experiments which yield information on the ripplon lifetimes. 19 refs., 4 figs.