| Abstract: | We investigate the relationship between the density matrix formalism and the method of describing quantum systems with wave functions pre-averaged over the thermostat states. It is shown that when fluctuations of the perturbation operator have a duration less than that of the characteristic times of variation of the isolated subsystem and the density matrix of the entire system can be represented as a direct product of the density matrix of the subsystem and the density matrix of the surrounding medium, both approaches lead to Neumann equations of the same structure. Omsk State Technical University. Translated fromIzvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 64–68, July, 1998. |
