Non-Markoviandynamicsofathree-levelquantumsystem

We investigate non-Markovian dynamics of a three-level system with the help of stochastic Schrodinger equation (SSE).The SSE has significant advantages agains tother approaches to open quantum systems. First of all, the dimension of the SSE is much smaller than the dimension of the corresponding master equation. Second, SSE ensures the complete positivity of the reduced density operatorin non-Markovian case,that is hard to achieve using other approaches. The above mentioned facts open a new efficient way for study quantum systems in higher dimensions in both Markovian and non-Markovian regimes

On the weak-coupling limit and complete positivity

We consider two non-interacting systems embedded in a heat bath. If they remain dynamically independent, physical inconsistencies are avoided only if the single-system reduced dynamics is completely positive also beyond the weak-coupling limit.Comment: 11 pages, plain-Te