title: Faster than Lyapunov decays of the classical Loschmidt echo.
abstract: We show that in the classical interaction picture the echo dynamics, namely, the composition of perturbed forward and unperturbed backward Hamiltonian evolution, can be treated as a time-dependent Hamiltonian system. For strongly chaotic (Anosov) systems we derive a cascade of exponential decays for the classical Loschmidt echo, starting with the leading Lyapunov exponent, followed by a sum of the two largest exponents, etc. In the loxodromic case a decay starts with the rate given as twice the largest Lyapunov exponent. For a class of perturbations of symplectic maps the echo dynamics exhibits a drift resulting in a superexponential decay of the Loschmidt echo.
authors.affiliation: Physics Department, FMF, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Gregor
authors.initials: G
authors.lastname: Veble
authors.forename: Tomaz
authors.initials: T
authors.lastname: Prosen