Small phase-space structures and their relevance to pulsed quantum evolution: Stepwise ionizationof the excited hydrogen atom in a microwave pulse

摘要

Experiments have shown that the microwave ionization probability of a highly excited, almost monodimen-sional, hydrogen atom subjected to a microwave pulse sometimes grows in steps when the peak electric field ofthe pulse is increased. Classical pulsed simulations display the same steps, which have been traced to phase-spacemetamorphoses. Quantum numerical calculations again exhibit the same ionization steps. I show that the timesequence of two-level interactions, responsible for the observed steps in the quantum picture, is strictly relatedto the classical phase-space structures generated by the above-mentioned metamorphoses.