Quantum diffusion in irregular crystals containing two-level tunnel systems

The quantum diffusion problem for admixture particles interacting with two-level tunnel systems (TLS) is investigated. It is shown that for the temperature range ₀ < T 1 K (where ₀ is the mean value of the energy level disturbance for admixture particles in the neighboring wells), and the TLS concentration is N_D 10²⁷ m^–3, the quantum diffusion coefficient for the admixture particles is determined by their interaction with the TLS's.Dedicated to the memory of Dmitri Nikolajevich ZubarevTranslated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 106, No. 3, pp. 489–497, March, 1996.Translated by A. R. Shirikyan.