Jan Derezinski, Rafal Fruboes
Fermi Golden Rule and open quantum systems
(485K, Postscript)

ABSTRACT.  We describe and compare two applications of the Fermi Golden Rule to the study of a small quantum system interacting with a reservoir. 
The first application is the weak coupling limit for the dynamics reduced to a subsystem. As a result one obtains a Markov completely positive semigroup generated by the so-called Davies generator. 
The second application is the computation of the Level Shift Operator for the Liouvillean, which is used in the problem of the return to equilibrium. We show that in the thermal case the Davies generator and the Level Shift Operator for the Liouvillean are related by a similarity transformation.