  An array of planar Penning traps, holding single electrons, can realize an
artificial molecule suitable for NMR-like quantum information processing. The
effective spin-spin coupling is accomplished by applying a magnetic field
gradient, combined to the Coulomb interaction acting between the charged
particles. The system lends itself to scalability, since the same substrate can
easily accommodate an arbitrary number of traps. Moreover, the coupling
strength is tunable and under experimental control. Our theoretical predictions
take into account a realistic setting, within the reach of current technology.
