CAPA-seminarium: Instabilities of quasi-periodic analytic tori

  • Datum:
  • Plats: Ångströmlaboratoriet 64119
  • Föreläsare: Gerard Puiggalí (KTH)
  • Kontaktperson: Alejandro Luque
  • Seminarium

Abstract: I will introduce recent results obtained in a joint work with Bassam Fayad concerning three types of stability properties for quasi-periodic invariant tori of Hamiltonian Systems:

The usual topological or Lyapunov stability, the stability in a measure theoretic or probabilistic sense (KAM stability), and the effective stability or quantitative stability in time. I will then focus on the proof for the existence of real analytic Hamiltonians with a Lyapunov unstable quasi-periodic torus. We will see that in the Diophantine case we can even obtain coexistence of diffusion and KAM stability (for more than two degrees of freedom).