Few-Body Quantum Dynamics in Relativistic Ion-Atom Collisions

Until recently the theory of relativistic ion-atom collisions was basically restricted to the description of the motion of a single electron in the external field generated by the atomic nucleus and that of the ion-projectile. In the present article we review some of the very recent developments in the theory of relativistic ion-atom collisions which go beyond the single-active-electron picture. Here we discuss processes in which two electrons actively participate and focus our attention in the following two kinds of such processes: (i) double ionization of helium by relativistically moving highly charged nuclei and (ii) two-center dielectronic transitions in relativistic collisions between an atom and an ion.