Order and Chaos in Classical and Quantum Mechanics

College Of William And Mary, Williamsburg VA

Investigators

Abstract

Research is proposed on semiclassical methods for calculating the behavior of quantum systems whose classical counterparts are chaotic. The primary focus will be on breakup of an excited complex. Of particular interest is the study of the ionization of atoms in electric and magnetic fields. If an atom is excited by a single-photon process from a strongly bound state by a short-pulse laser, A + hv = A*, and then the excited state decays, A* = A+ + e-, it is possible to measure the time between the laser pulse and the appearance of an electron at a detector. Such measured "time spectra" do not show exponential decay; instead, electrons appear at the detector in a train of pulses. These pulses are related to classical orbits of the electron. Calculations based upon classical mechanics indicate that these chaotic pulse-trains are described by a kind of fractal. We are analyzing the structure of such fractals and making predictions of results of future experiments. In addition we will continue to apply closed-orbit theory to atomic spectra. There are new experimental measurements in several laboratories, and we will help to provide theoretical interpretation of these measurements.