Non-Reversible Evolution of Quantum Chaotic System. Kinetic Description
  Time dependent dynamics of the chaotic quantum-mechanical system has been studied. Irreversibility of the dynamics is shown. It is shown, that being in the initial moment in pure quantum-mechanical state, system makes irreversible transition into mixed state. Original mechanism of mixed state formation is offered. Quantum kinetic equation is obtained. Growth of the entropy during the evolution process is estimated. 
L. Chotorlishvili, V. Skrinnikov