EFFECTIVE 2-LEVEL REDUCTION OF N-LEVEL SYSTEM DISSIPATIVE QUANTUM DYNAMICS

A projection method that enables transformation of N-level/site dissipative dynamics into an equivalent set of effective two-level/site dynamics has been proposed. The method takes into account in a consistent manner the effect of complementary (N-2) levels on the dynamics of effective two-level systems. The corresponding equation of motion for the reduced-dissipative density matrix has been derived in a general form. The method has been applied to a model study of particle transfer in a double well potential characterized by four energy levels. It is shown that inclusion of excited states results in opening of new transport channel. This mechanism holds even when the Boltzmann population of excited states is very small. © 1990.