  The exotic nucleus 11Be has been extensively studied and much experimental
information is available on the structure of this system. Treating, within the
framework of empirically renormalised nuclear field theory in both
configuration and 3D-space, the mixing of bound and continuum single-particle
states through the coupling to collective particle-hole (p,h) and pairing
vibrations of the 10Be core, as well as Pauli principle acting not only between
the particles explicitly considered and those participating in the collective
states, but also between fermions involved in two-phonon virtual states it is
possible, for the first time, to simultaneously and quantitatively account for
the energies of the 1/2+,1/2- low-lying states, the centroid and line shape of
the 5/2+ resonance, the one-nucleon stripping and pickup absolute differential
cross sections involving 11Be as either target or residual nucleus, and the
dipole transitions connecting the 1/2+ and 1/2- parity inverted levels as well
as the charge radius, thus providing a unified and exhaustive characterisation
of the many-body effects which are at the basis of this paradigmatic
one-neutron halo system.
