4 papers
Degenerate elliptic resonances
Guido Gentile Giovanni Gallavotti
Quasi-periodic motions on invariant tori of an integrable system of dimension smaller than half the phase space dimension may continue to exists after small perturbations. The para…
Bryuno Function and the Standard Map
Alberto Berretti, Guido Gentile
For the standard map the homotopically non-trivial invariant curves of rotation number satisfying the Bryuno condition are shown to be analytic in the perturbative parameter, provi…
Peierls instability for the Holstein model
G. Benfatto, G. Gentile, V. Mastropietro
We consider the static Holstein model, describing a chain of Fermions interacting with a classical phonon field, when the interaction is weak and the density is a rational number.…
Hamilton-Jacobi equation, heteroclinic chains and Arnol'd diffusion in three time scales systems
Giovanni Gallavotti, Guido Gentile, Vieri Mastropietro
Interacting systems consisting of two rotators and a point mass near a hyperbolic fixed point are considered, in a case in which the uncoupled systems have three very different cha…