  The paper studies a class of quantum stochastic differential equations,
modeling an interaction of a system with its environment in the quantum noise
approximation. The space representing quantum noise is the symmetric Fock space
over L^2(R_+). Using the isomorphism of this space with the space of
square-integrable functionals of the Poisson process, the equations can be
represented as classical stochastic differential equations, driven by Poisson
processes. This leads to a discontinuous dynamical state reduction which we
compare to the Ghirardi-Rimini-Weber model. A purely quantum object, the norm
process, is found which plays the role of an observer (in the sense of Everett
[H. Everett III, Reviews of modern physics, 29.3, 454, (1957)]), encoding all
events occurring in the system space. An algorithm introduced by Dalibard et al
[J. Dalibard, Y. Castin, and K. M{\o}lmer, Physical review letters, 68.5, 580
(1992)] to numerically solve quantum master equations is interpreted in the
context of unravellings and the trajectories of expected values of system
observables are calculated.
