On the quantum dissipative generator:: weak-coupling approximation and stochastic approach

For a quantum open system the so-called Schrodinger-Langevin picture has been revisited. In a second-order perturbation it is shown that a non-Markovian evolution for the stochastic state vector leads to a dissipative generator which has a Kossakowski-Lindblad form. In this context it is possible to analyse the completely positive condition. The equivalence of this picture with the trace-out technique in the weak coupling approximation has been proved.