Diffusion in two-component quasiparticle systems of liquid and solid mixtures of helium isotopes

摘要

An exact expression for the diffusion time which depends on the interaction rates for particles of not only different, but also of the same species,udhas been derived from the system of kinetic equations. The result is validudfor particles with arbitrary statistics and energy-momentum relations. Theudderived general relations are valid for investigating diffusion in liquid andudsolid ³He-⁴He mixtures. The contribution of interaction between quasiparticles of the same type to the diffusion coefficient and effective thermaludconductivity of superfluid solutions is analyzed. The calculated values areudcompared with experimental data. The calculated diffusion coefficient ofud³He-⁴He solid solutions differs from the previous theoretical results. A comparison of the obtained diffusion coefficient with experimental data makesudit possible to determine the numerical value of the energy band width forudimpurity quasiparticles.