RELAXATION JUMPS OF STRONG VIBRATION

A nonperturbative theory of two-phonon relaxation of a strongly excite d local mode is developed, whereby the mode is considered classically and phonons, quantum mechanically. The relaxation mechanism is analogo us to that of black hole emission proposed by Hawking: it consists of linear transformation of phonon operators in time, which is induced by the classical subsystem (mode). Due to this transformation the number of phonons increases while the energy of the local mode decreases in time. It is found that there exist some critical energies of the local mode when relaxation rate is strongly enhanced. Thereby relaxation ju mps take place, which are accompanied by generation of bursts of phono ns. The values of the critical energies do not depend on temperature. The final stage of relaxation is exponential, in agreement with pertur bation theory. Numerical calculations of the relaxation jumps are pres ented.