Disturbance propagation in chaotic extended systems with long-range coupling

Propagation of initially localized perturbations is investigated in chaotic coupled map lattices with long-range couplings decaying as a power of the distance. The initial perturbation propagates exponentially fast along the lattice, with a rate given by the ratio of the maximal Lyapunov exponent and the power of the coupling. A complementary description in terms of a suitable comoving Lyapunov exponent is also given.