Random fluctuation leads to forbidden escape of particles

Christian S. Rodrigues, Alessandro P.S. de Moura, and Celso Grebogi

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Submission date: 08. Oct. 2010
published in: Physical review / E, 82 (2010) 2, art-no. 026211 
DOI number (of the published article): 10.1103/PhysRevE.82.026211
Bibtex
PACS-Numbers: 05.45.Ac, 61.43.Hv
Keywords and phrases: random perturbation of Nonhyperbolic dynamics, chaotic scattering dynamics

Abstract:
A great number of physical processes are described within the context of Hamiltonian scattering. Previous studies have rather been focused on trajectories starting outside invariant structures, since the ones starting inside are expected to stay trapped there forever. This is true though only for the deterministic case. We show however that, under finitely small random fluctuations of the field, trajectories starting inside Kolmogorov-Arnold-Moser (KAM) islands escape within finite time. The nonhyperbolic dynamics gains then hyperbolic characteristics due to the effect of the random perturbed field. As a consequence, trajectories which are started inside KAM curves escape with hyperboliclike time decay distribution, and the fractal dimension of a set of particles that remain in the scattering region approaches that for hyperbolic systems. We show a universal quadratic power law relating the exponential decay to the amplitude of noise. We present a random walk model to relate this distribution to the amplitude of noise, and investigate these phenomena with a numerical study applying random maps.