Investigation of the phonon dispersion relation in liquid /sup 4/He by thermal-expansion measurements

Journal Article · Wed Sep 01 04:00:00 EDT 1976 · Phys. Rev., B; (United States)

DOI:https://doi.org/10.1103/PhysRevB.14.1902· OSTI ID:7358133

Berthold, J E; Hanson, H N; Maris, H J; Seidel, G M

The thermal expansion of superfluid /sup 4/He under the saturated vapor pressure has been measured in the temperature range 0.1--0.62 K. The expansion was found by filling a superconducting resonant cavity with the liquid and measuring the resonant frequency as a function of temperature. The density was related to the dielectric constant through the Clausius-Mossotti relation. Sensitivity to changes in fractional density of 4 x 10/sup -9/ was achieved. The thermal-expansion data were used to obtain quantitative information about the dispersion relation for thermal phonons. In addition to the thermal-expansion measurements, tests of the validity of the Clausius-Mossotti relation were made. (AIP)

• Research Organization: Department of Physics, Brown University, Providence, Rhode Island 02912
• OSTI ID: 7358133
• Journal Information: Phys. Rev., B; (United States), Journal Name: Phys. Rev., B; (United States) Vol. 14:5; ISSN PLRBA
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
DENSITY
DISPERSION RELATIONS
EVEN-EVEN NUCLEI
EXPANSION
HELIUM 4
HELIUM ISOTOPES
ISOTOPES
LIGHT NUCLEI
NUCLEI
PHONONS
PHYSICAL PROPERTIES
QUASI PARTICLES
STABLE ISOTOPES
SUPERFLUIDITY
THERMAL EXPANSION
ULTRALOW TEMPERATURE