  A "dispersive quantum system" is a quantum system which is both isolated and
non-time reversal invariant. This article presents precise definitions for
those concepts and also a characterization of dispersive quantum systems within
the class of completely positive Markovian quantum systems in finite dimension
(through a homogeneous linear equation for the non-Hamiltonian part of the
system's Liouvillian). To set the framework, the basic features of quantum
mechanics are reviewed focusing on time evolution and also on the theory of
completely positive Markovian quantum systems, including Kossakowski-Lindblad's
standard form for Liouvillians. After those general considerations, I present a
simple example of dispersive two-level quantum system and apply that to
describe neutrino oscillation.
