PHASE-SPACE LOCALIZATION AND LEVEL SPACING DISTRIBUTIONS FOR A DRIVENROTOR WITH MIXED REGULAR CHAOTIC DYNAMICS/

The classical-quantum correspondence for systems with mixed regular an d chaotic dynamics can be conveniently analyzed by the quantum Husimi phase-space distribution. The entropy of this distribution can be used to classify the quantum states as ''regular'' or ''chaotic''. The nea rest-neighbor statistics is then investigated for different classes of states and compared with the semiclassical Berry-Robnik distribution to verify this classification and the assumption of uncorrelated spect ra of different classes, Moreover, the phase-space entropy provides a global picture of quantum phase-space structures similar to the classi cal Poincare section, Numerical results for a time periodic system wit h one degree of freedom monochromatically driven by an external force demonstrate the validity and usefulness of these semiclassical concept s. (C) 1997 Elsevier Science B.V.