title: Exact fidelity and full fidelity statistics in regular and chaotic surroundings.
abstract: For a prepared state exact expressions for the time-dependent mean fidelity as well as for the mean inverse participation ratio are obtained analytically. The prepared state is taken as an eigenstate of the unperturbed system, and the studied fidelity is identical to the survival probability. The full distribution functions of fidelity in the long-time limit and of inverse participation ratio are studied numerically and analytically. Surprising features such as fidelity revival and nonergodicity are observed. The roles of the coupling coefficients and of complexity of background are studied as well.
authors.affiliation: Fakultät für Physik, Universität Duisburg-Essen, 47057 Duisburg, Germany.
authors.forename: Heiner
authors.initials: H
authors.lastname: Kohler
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Sommers
authors.forename: Sven
authors.initials: S
authors.lastname: Aberg
authors.forename: Thomas
authors.initials: T
authors.lastname: Guhr