  "Quantum mechanics must be regarded as open systems. On one hand, this is due
to the fact that, like in classical physics, any realistic system is subjected
to a coupling to an uncontrollable environment which influences it in a
non-negligible way. The theory of open quantum systems thus plays a major role
in many applications of quantum physics since perfect isolation of quantum
system is not possible and since a complete microscopic description or control
of the environment degrees of freedom is not feasible or only partially so"
[1]. Practical considerations therefore force one to seek for a simpler,
effectively probabilistic description in terms of an open system. There is a
close physical and mathematical connection between the evolution of an open
system, the state changes induced by quantum measurements, and the classical
notion of a stochastic process. The paper provides a bibliographic review of
this interrelations, it shows the mathematical equivalence between markovian
master equation and generalized piecewise deterministic processes [1] and it
introduces the open system in an open observed environment model.
