Roton second sound and roton scattering

Journal Article · Wed Apr 01 04:00:00 EST 1981 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.23.3308· OSTI ID:6535142

Maris, H J; Cline, R W

The theory of roton second sound in superfluid helium-4 is considered. We first derive the hydrodynamic equations which determine the motion of a pure roton gas. The collisions between rotons are assumed to conserve energy, momentum, and the number of rotons. The hydrodynamic equations without dissipative terms have the same form as the corresponding equations for an ordinary fluid. When lowest-order dissipative effects are included, it is found that there are some extra dissipative processes in addition to heat conduction and viscosity. We next consider modifications of the hydrodynamic equations which occur when the effects of collisions between rotons and phonons are included, and when there are some roton-roton collisions in which the roton number changes. It is found that at the temperatures and pressures where roton second sound has so far been observed, the wave motion is best described as isothermal second sound. We show that current experimental data indicate that in nearly all collisions between rotons (>99.97%) the total number of rotons is conserved.

• Research Organization: Department of Physics, Brown University, Providence, Rhode Island 02912
• OSTI ID: 6535142
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 23:7; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COLLISIONS
EVEN-EVEN NUCLEI
FLUIDS
HELIUM 4
HELIUM II
HELIUM ISOTOPES
ISOTOPES
LIGHT NUCLEI
NUCLEI
QUANTUM FLUIDS
QUASI PARTICLES
ROTONS
SCATTERING
SECOND SOUND
STABLE ISOTOPES
SUPERFLUIDITY