Energy localization and propagation in disordered media: low-temperature thermal conductivity of amorphous materials
Burin A. L., Maksimov L. A. , Polishchuk I. Ya.
The model of two-level systems with an interaction U(R)~R~a is used to show that delocalized collective excitations exist in disordered media for a < 6. The low-temperature thermal conductivity resulting from these excitations is calculated. The behavior /с~ Т4/3 is found for a = 3.