DYNAMIC BARRIERS TO TRANSPORT IN PULSED SPIN SYSTEMS - QUANTUM CLASSICAL CORRESPONDENCE IN THE KICKED TOP

Classical phase space is not homogeneous, but contains barriers (such as KAM tori) that, whether intact or broken, affect the temporal evolution of dynamical systems. In this article, we study the quantal manifestations of these classical-mechanical structures. Here, the particular system is the kicked top, which consists of an angular momentum vector precessing about one direction and experiencing periodic sudden kicks around another direction. We find that a suitably defined probability distribution function (constructed from the time-dependent state vector) shows transitions from classically allowed regions to inaccessible regions at the locations where the classical dynamics places the KAM tori.