Quantum diffusion in irregular crystals having tunnel two-level systems

The quantum diffusion of admixture particles interacting with tunnel two-level systems is studied. It is shown that in the temperature region $\omega_0<T\lesssim 1$K, where $\omega_0$ is an average value of the energy disturbance of admixture particles in the neighbouring pits, and under the concentration $N_D\gtrsim 10^{27}\text m^{-3}$ of two-level systems the quantum diffusion coefficient of admixture particles is determined by their interaction with two-level systems.