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Super-diffusion in optical realizations of Anderson localization

Krivolapov, Yevgeny; Levi , Liad; Fishman, Shmuel; Segev, Mordechai and Wilkinson, Michael (2012). Super-diffusion in optical realizations of Anderson localization. New Journal of Physics, 14 043047.

URL: http://iopscience.iop.org/1367-2630/14/4/043047/
DOI (Digital Object Identifier) Link: http://dx.doi.org/10.1088/1367-2630/14/4/043047
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Abstract

We discuss the dynamics of particles in one dimension in potentials that are random in both space and time. The results are applied to recent optics experiments on Anderson localization, in which the transverse spreading of a beam is suppressed by random fluctuations in the refractive index. If the refractive index fluctuates along the direction of the paraxial propagation of the beam, the localization is destroyed. We analyze this broken localization in terms of the spectral decomposition of the potential. When the potential has a discrete spectrum, the spread is controlled by the overlap of Chirikov resonances in phase space. As the number of Fourier components is increased, the resonances merge into a continuum, which is described by a Fokker–Planck equation. We express the diffusion coefficient in terms of the spectral intensity of the potential. For a general class of potentials that are commonly used in optics, the solutions to the Fokker–Planck equation exhibit anomalous diffusion in phase space, implying that when Anderson localization is broken by temporal fluctuations of the potential, the result is transport at a rate similar to a ballistic one or even faster. For a class of potentials which arise in some existing realizations of Anderson localization, atypical behavior is found.

Item Type: Journal Article
Copyright Holders: 2012 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft
ISSN: 1367-2630
Extra Information: 16 pp.
Academic Unit/Department: Mathematics, Computing and Technology > Mathematics and Statistics
Item ID: 35496
Depositing User: Michael Wilkinson
Date Deposited: 23 Nov 2012 09:11
Last Modified: 30 Nov 2012 16:50
URI: http://oro.open.ac.uk/id/eprint/35496
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