QUANTUM AVERAGING - III - TIME-DEPENDENT SYSTEMS

We present new perturbation algorithms for time-dependent quantum syst ems. These new methods make use of a time-dependent averaging method a nd are based on analogies with the Poincare-von Zeipel (PvZ) and Kolmo gorov-Arnold-Moser (KAM) expansions. Application to a simple example s hows that the PvZ as well as the KAM expansion are superior to the sta ndard quantum mechanical time-dependent perturbation method (Dyson exp ansion). (C) 1998 American Institute of Physics.