title: Fidelity decay for local perturbations: microwave evidence for oscillating decay exponents.
abstract: We study fidelity decay in classically chaotic microwave billiards for a local, pistonlike boundary perturbation. We experimentally verify a predicted nonmonotonic crossover from the Fermi golden rule to the escape-rate regime of the Loschmidt echo decay with increasing local boundary perturbation. In particular, we observe pronounced oscillations of the decay rate as a function of the piston position which quantitatively agree with corresponding theoretical results based on a refined semiclassical approach for local boundary perturbations.
authors.affiliation: Fachbereich Physik der Philipps-Universität Marburg, D-35032 Marburg, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Köber
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kuhl
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Stöckmann
authors.forename: Arseni
authors.initials: A
authors.lastname: Goussev
authors.forename: Klaus
authors.initials: K
authors.lastname: Richter