Физика Низких Температур: Том 23, Выпуск 5-6 (Май 1997), c. 537-545 ( к оглавлению , назад )
Viscosity and ultrasonic attenuation in 4 He below 0.6 K
I. N. Adamenko
Department of Physics and Technology, Kharkov State University, Kharkov 310077, Ukraine
L. N. Pandey
Departments of Chemistry and Physics, Washington State University, Pullman, Washington 99164-4630, U.S.A.
T. F. George
Office of the Chancellor / Departments of Chemistry and Physics and Astronomy,University of Wisconsin-Stevens Point, Stevens Point, Wisconsin 54481-3897, U.S.A.
Department of Physics, Seonam University, Namwon, Chunbuk 590-170, Korea
(Submitted November 29, 1996)
Through a treatment of three-phonon processes, the wide-angle scattering rates and the absorption rates of phonons, which characterize viscosity and ultrasonic attenuation, respectively, are calculated for 4He below 0.6K. These rates are obtained from the collision matrix which is constructed approximately from an integral eigenvalue equation for the collision operator. The sequence of the lowest eigenvalues of the collision matrix, as the angular momentum quantum number l increases, shows a saturated behavior which has not been reported before. The calculated viscosity and ultrasonic attenuation are compared with previous theoretical and experimental results.