CLASSICAL-QUANTUM CORRESPONDENCE IN THE DRIVEN SURFACE-STATE-ELECTRONMODEL

The quantum dynamics of minimum uncertainty wave packets in a system d escribed by the surface-state-electron Hamiltonian are studied herein. The quantum evolution is found to be strongly dependent upon the orbi t structure in the classical phase space. A Gaussian wave packet, init ially centered on the part of the phase space incased by Kolmogorov-Ar nold-Moser tori remains localized, while the packets located in the ch aotic region spread rapidly, filling the available phase space. To qua ntify the observed spreading quantum uncertainty is introduced as a dy namical variable, and its time development is determined by the ballis tic growth of the position uncertainty and the erratic oscillations of the momentum uncertainty. The quantum evolution is analyzed within th e framework of the Floquet formalism. The Floquet spectrum of the stab le packet is shown to be dominated by a few quasienergy states with th e corresponding Husimi distribution embedded in the classical stabilit y island. Further, the classical concept of diffusion previously used in this context is shown to be inappropriate.