SOME REMARKS CONCERNING STABILITY FOR NONSTATIONARY QUANTUM-SYSTEMS

The problem of characterizing stability and instability for general no nstationary quantum systems is investigated. Some characterizations ar e reported and some elementary properties of a topological characteriz ation are established. Then, it is proven, by considering a simple exa mple, that there are nonperiodic driven systems whose orbits are neith er precompact nor leave on average any compact set. Autocorrelation me asures are computed and the possible roles of the generalizes quasiene rgy operator and energy growth are briefly discussed.