New results on non-CP dynamics unearthed from urtexts of quantum state diffusion

Thirty years ago, the present author discussed the pure state unraveling (stochastic quantum trajectories) of Markovian open system dynamics. The fact that he considered all positive dynamics, not restricted to the Lindblad-Gorini-Kossakowski-Sudarshan complete-positive subclass, has remained unnoticed so far. We emphasize the importance of the transition-rate-operator W and the merit of the invariant (representation-independent) approach. From the urtexts we point out the condition W 0 of positive dynamics, the extension of quantum state diffusion for positive dynamics, and as a major new result, the description of all the diffusive unravelings of positive dynamics.