Nuclei far from stability: from bound to unbound systems

11h - Salle des séminaires du GANIL

Weakly bound nuclear systems can be considered to represent a good testing-ground of our understanding of non-perturbative quantum systems. Great progress in experimental sensitivity has been attained by increase in rare isotope beam intensities and by the development of new high efficiency detectors. It is now possible to study reactions leading to bound and unbound states in systems with very unbalanced neutron to proton ratios. Secondary beams with energies from below the Coulomb barrier up to several hundreds MeV/nucleon are now available, and with these beams, a broad variety of studies of nuclei near the drip-line can be performed. Coupling to continuum becomes an important aspect, and reaction and structure cannot be longer treated in a perturbative manner. This may be related to the description of non-perturbative phenomena, a very general subject, of importance in many problems, such as physics of complex systems.  An illustration the importance of non-perturbative effects is the necessity in recent “ab initio” calculations to take into account 3-body forces: the interaction between two nucleons is modified by the presence of a third nucleon. Recent results on light systems, A~10, will be described in this context. Collective excitations in heavier nuclei far from stability is another subject of great progress recently. Some results will be shown, and future prospects will be discussed.