M. Kaufmann, W. Muschik and D. Schirrmeister
On positivity of rate of entropy in quantum-thermodynamics
in: J. S. Shiner (Ed.): Entropy and Entropy Generation
Kluwer, Dordrecht 1996, 1 - 9

The rate of entropy is discussed for several different dynamics of the generalized canonical operator: Canonical dynamics, Robertson dynamics, and contact time dynamics. For two discrete systems in contact the rate of entropy is positive definite, if the contact time is short, and if one of the two discrete systems is in equilibrium and the compound system of both is isolated.