title: Consequences of flooding on spectral statistics.
abstract: We study spectral statistics in systems with a mixed phase space, in which regions of regular and chaotic motion coexist. Increasing their density of states, we observe a transition of the level-spacing distribution P(s) from Berry-Robnik to Wigner statistics, although the underlying classical phase-space structure and the effective Planck constant h(eff) remain unchanged. This transition is induced by flooding, i.e., the disappearance of regular states due to increasing regular-to-chaotic couplings. We account for this effect by a flooding-improved Berry-Robnik distribution, in which an effectively reduced size of the regular island enters. To additionally describe power-law level repulsion at small spacings, we extend this prediction by explicitly considering the tunneling couplings between regular and chaotic states. This results in a flooding- and tunneling-improved Berry-Robnik distribution which is in excellent agreement with numerical data.
authors.affiliation: Institut für Theoretische Physik, Technische Universität Dresden, 01062 Dresden, Germany.
authors.forename: Torsten
authors.initials: T
authors.lastname: Rudolf
authors.forename: Normann
authors.initials: N
authors.lastname: Mertig
authors.forename: Steffen
authors.initials: S
authors.lastname: Löck
authors.forename: Arnd
authors.initials: A
authors.lastname: Bäcker