STATES OF A DYNAMICALLY DRIVEN SPIN .2. CLASSICAL-MODEL AND THE QUANTUM-TO-CLASSICAL LIMIT

A classical spin, dynamically driven by a polarized beam, is shown to exhibit a complex variety of behaviors, including stable fixed points, bifurcations, limit cycles, and choas. In the classical (large-spin) limit of the corresponding quantum model, the probability distributions for the spin components converge to their classical counterparts, even though the classical motions are qualitatively different for different ranges of parameters. However, the nature of the quantum-to-classical limit has some unexpected features, which are discussed.