%0 Journal Article
%A Creffield, Charles
%A Hur, G.
%A Monteiro, T. S.
%T Localization-delocalization transition in a system of quantum kicked rotors
%D 2006
%@ 0031-9007
%U https://hdl.handle.net/20.500.14352/51583
%X The quantum dynamics of atoms subjected to pairs of closely spaced delta kicks from optical potentials are shown to be quite different from the well-known paradigm of quantum chaos, the single delta-kick system. We find the unitary matrix has a new oscillating band structure corresponding to a cellular structure of phase space and observe a spectral signature of a localization-delocalization transition from one cell to several. We find that the eigenstates have localization lengths which scale with a fractional power L similar to h(-0.75) and obtain a regime of near-linear spectral variances which approximate the "critical statistics" relation Sigma(2)(L)similar or equal to chi L approximate to 1/2(1-nu)L, where nu approximate to 0.75 is related to the fractal classical phase-space structure. The origin of the nu approximate to 0.75 exponent is analyzed.
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