Quantum mechanics is the set of laws of physics which, to the best of
our knowledge, provides a complete account of the microworld. One of its
chap- ters, quantum electrodynamics (QED), is able to account for the
quantal phenomena of relevance to daily life (electricity, light,
liquids and solids, etc.) with great accuracy. The language of QED,
field theory, has proved to be uni- versal providing the theoretical
basis to describe the behaviour of many-body systems. In particular
finite many-body systems (FMBS) like atomic nuclei, metal clusters,
fullerenes, atomic wires, etc. That is, systems made out of a small
number of components. The properties of FMBS are expected to be quite
different from those of bulk matter, being strongly conditioned by
quantal size effects and by the dynamical properties of the surface of
these systems. The study of the elec- tronic and of the collective
behaviour (plasmons and phonons) of FMBS and of their interweaving,
making use of well established first principle quantum (field
theoretical) techniques, is the main subject of the present monograph.
The interest for the study of FMBS was clearly stated by Feynman in his
address to the American Physical Society with the title "There is plenty
of room at the bottom". On this occasion he said among other things:
"When we get to the very, very small world - say circuits of seven
atoms - we have a lot of new things that would happen that represent
completely new opportunities for design" [1].