Diffusion of thermal and impurity excitations in superfluid mixtures of helium isotopes

Abstract

The matrix of dissipative coefficients was calculated starting from the system of kinetic equations. These coefficients determine the diffusion flows in three-component gas without any restrictions on statistics and dispersion laws of particles. All diffusion coefficients of superfluid³ He− ⁴ He solutions were obtained from these general relations. The diffusion flow of phonons and rotons is shown to define nonadditive part of thermal conductivity. The obtained relations for coefficient of spin diffusion strictly differs from the empirical formulae used so far that include the coefficient of mass diffusion. The theoretical results have been compared with experimental data.