Instabilities of analytic quasi-periodic tori
schedule le mardi 17 décembre 2019 de 10h30 à 12h00
Organisé par : David Burguet, Yves Coudene et Pierre-Antoine Guiheneuf
Intervenant : Gerard Farre (KTH)
Lieu : salle Paul Levy (Jussieu salle 16.26.209)
Sujet : Instabilities of analytic quasi-periodic tori
We will present the results of a recent joint work with B.Fayad on the stability of quasi-periodic tori for Hamiltonian systems. In particular, we show the existence of real analytic Hamiltonians with a Lyapunov unstable quasi-periodic torus of arbitrary frequency. Furhtermore, for Diophantine frequencies these tori can be chosen to be KAM stable, meaning that the original torus is accummulated by a set of invariant tori whose relative measure tends to one. We will also present some other similar interesting examples in the context of stability of invariant quasi-periodic tori.