COUPLING BETWEEN SLOW AND FAST DEGREES OF FREEDOM IN SYSTEMS WITH COMPLEX SPECTRA - DRIVEN SYSTEMS

We consider many-body systems which display slow modes and have comple x spectra of intrinsic states, as atomic nuclei, atomic clusters, defo rmable cavities, and so forth. The effects of the coupling between the intrinsic and the slow degrees of freedom is analyzed, by assuming ra ndom matrix properties for the intrinsic degrees of freedom and the fa ct that the time evolution of the slow degrees of freedom modifies the intrinsic configuration of the system. By neglecting the reaction of the intrinsic degrees of freedom on the slow modes, we derive evolutio n equations for intrinsic state population probabilities, the average excitation energy, and their fluctuations. These evolution equations a re characterized by strong memory effects, and only in the long time l imit does the dynamics become Markovian. (C) 1995 Academic Press, Inc.