Generalized Lyapunov exponents of the random harmonic oscillator:   cumulant expansion approach
  The cumulant expansion is used to estimate generalized Lyapunov exponents of the random-frequency harmonic oscillator. Three stochastic processes are considered: Gaussian white noise, Ornstein-Uhlenbeck, and Poisson shot noise. In some cases, nontrivial numerical difficulties arise. These are mostly solved by implementing an appropriate importance-sampling Montecarlo scheme. We analyze the relation between random-frequency oscillators and many-particle systems with pairwise interactions like the Lennard-Jones gas. 
Raul Vallejos and Celia Anteneodo
cond-mat.stat-mech nlin.CD