  We report on the experimental investigation of an individual pseudomolecule
using trapped ions with adjustable magnetically induced J-type coupling between
spin states. Resonances of individual spins are well separated and are
addressed with high fidelity. Quantum gates are carried out using microwave
radiation in the presence of thermal excitation of the pseudomolecule's
vibrations. Demonstrating Controlled-NOT gates between non-nearest neighbors
serves as a proof-of-principle of a quantum bus employing a spin chain.
Combining advantageous features of nuclear magnetic resonance experiments and
trapped ions, respectively, opens up a new avenue towards scalable quantum
information processing.
