Quantum diffusion ofHe3impurities in solidHe4

Abstract

A theoretical analysis is presented for the temperature dependence of the diffusion of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ impurities in solid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ in the regime where the coherent impurity motion at low temperatures is interrupted by scattering from vacancies or phonons. It is shown that the observed temperature dependences can be accurately described by a model involving vacancy scattering.