title: Quantum suppression of microwave ionization of Rydberg atoms at high scaled frequency.
abstract: Microwave ionization of Rydberg atoms is well described as the onset of classical chaos when the microwave frequency omega is less than the Kepler frequency 1/n(3). However, when omega>1/n(3), i.e., at high scaled frequency Omega=omegan(3)>1, classical ionization is predicted to be suppressed by quantum interference, an analogue to Anderson localization in a solid. Using 17.55 GHz microwave fields we have observed the ionization of Sr Rydberg atoms in the regime 1</=Omega</=5 . Our measurements demonstrate the quantum suppression of classical diffusive ionization and show the ionization field to be n independent in this regime.
authors.affiliation: Department of Physics, University of Virginia, Charlottesville, Virginia 22904-0714, USA.
authors.forename: H
authors.initials: H
authors.lastname: Maeda
authors.forename: T F
authors.initials: TF
authors.lastname: Gallagher