  The wide-spread opinion is that original quantum mechanics is a reversible
theory, but this statement is only true for undecomposed systems, that are
those systems which sub-systems are out of consideration. Taking sub-systems
into account, as it is by definition necessary for decomposed systems, the
interaction Hamiltonians which are absent in undecomposed systems generate
irreversibility. Thus, the following two-stage task arises: How to modify von
Neumann's equation for undecomposed systems so that irreversibility appears,
and how this modification affects decomposed systems ? The first step was
already done and is repeated below, whereas the second step to formulate a
quantum thermodynamics of decomposed systems is performed here by modifying the
von Neumann equations of the sub-systems by a procedure wich is similar to that
of Lindblad's equation, but different because the sub-systems interact with one
another through partitions.
