title: Fractional-power-law level statistics due to dynamical tunneling.
abstract: For systems with a mixed phase space we demonstrate that dynamical tunneling universally leads to a fractional power law of the level-spacing distribution P(s) over a wide range of small spacings s. Going beyond Berry-Robnik statistics, we take into account that dynamical tunneling rates between the regular and the chaotic region vary over many orders of magnitude. This results in a prediction of P(s) which excellently describes the spectral data of the standard map. Moreover, we show that the power-law exponent is proportional to the effective Planck constant h(eff).
authors.affiliation: Institut für Theoretische Physik, Technische Universität Dresden, 01062 Dresden, Germany.
authors.forename: Arnd
authors.initials: A
authors.lastname: Bäcker
authors.forename: Roland
authors.initials: R
authors.lastname: Ketzmerick
authors.forename: Steffen
authors.initials: S
authors.lastname: Löck
authors.forename: Normann
authors.initials: N
authors.lastname: Mertig