L. Lanz et B. Vacchini, DYNAMICAL SEMIGROUP DESCRIPTION OF COHERENT AND INCOHERENT PARTICLE-MATTER INTERACTION, International journal of theoretical physics, 36(1), 1997, pp. 67-88
The meaning of statistical experiments with single microsystems in qua
ntum mechanics is discussed and a general model in the framework of no
nrelativistic quantum field theory is proposed to describe both cohere
nt and incoherent interaction of a single microsystem with matter. Com
pactly developing the calculations with superoperators, it is shown th
at the introduction of a time scale linked to irreversibility of the r
educed dynamics directly leads to a dynamical semigroup expressed in t
erms of quantities typical of scattering theory. Its generator consist
s of two terms, the first linked to a coherent wavelike behavior, the
second related to an interaction having a measuring character, possibl
y connected to events the microsystem produces propagating inside matt
er. In case these events breed a measurement, an explicit realization
of some concepts of modern quantum mechanics (''effects'' and ''operat
ions'') arises. The relevance of this description to a recent debate q
uestioning the validity of ordinary quantum mechanics to account for s
uch experimental situations as, e.g., neutron interferometry is briefl
y discussed.