Localization and relaxation in quantum systems 

  Giulio Casati
Center for Nonlinear and Complex Systems
Universita' degli studi dell'Insubria- Via Valleggio, 11 - 22100 Como
(giulio.casati@unisubria.it)

We study the interplay between quantum localization and the rich structure of the classical phase space of chaotic billiards which exhibit classical diffusive behaviour.
We also discuss how quantum localization affects the quantum survival probability in open quantum systems. The physical example of the time dependence of ionisation probability in Rydberg atoms is considered in particular. The analysis of these models leads to new insight in the understanding of quantum properties of classically chaotic systems.