  We perform strategic current injection in a small mesoscopic superconductor
and control the (non)equilibrium quantum states in an applied homogeneous
magnetic field. In doing so, we realize a current-driven splitting of
multi-quanta vortices, current-induced transitions between states with
different angular momenta, and current-controlled switching between otherwise
degenerate quantum states. These fundamental phenomena form the basis for
discussed electronic and logic applications, and are confirmed in both
theoretical simulations and multiple-small-tunnel-junction transport
measurements.
