title: Fractional variant Planck's over 2pi scaling for quantum kicked rotors without Cantori.
abstract: Previous studies of quantum delta-kicked rotors have found momentum probability distributions with a typical width (localization length L) characterized by fractional variant Planck's over 2pi scaling; i.e., L approximately variant Planck's over 2pi;{2/3} in regimes and phase-space regions close to "golden-ratio" cantori. In contrast, in typical chaotic regimes, the scaling is integer, L approximately variant Planck's over 2pi;{-1}. Here we consider a generic variant of the kicked rotor, the random-pair-kicked particle, obtained by randomizing the phases every second kick; it has no Kol'mogorov-Arnol'd-Moser mixed-phase-space structures, such as golden-ratio cantori, at all. Our unexpected finding is that, over comparable phase-space regions, it also has fractional scaling, but L approximately variant Planck's over 2pi;{-2/3}. A semiclassical analysis indicates that the variant Planck's over 2pi;{2/3} scaling here is of quantum origin and is not a signature of classical cantori.
authors.affiliation: Temasek Laboratories, National University of Singapore, 117542 Singapore.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: T S
authors.initials: TS
authors.lastname: Monteiro
authors.forename: S
authors.initials: S
authors.lastname: Fishman
authors.forename: J P
authors.initials: JP
authors.lastname: Keating
authors.forename: R
authors.initials: R
authors.lastname: Schubert