  We demonstrate coherent control of two nuclear spins mediated by the magnetic
resonance of a hyperfine-coupled electron spin. This control is used to create
a double nuclear coherence in one of the two electron spin manifolds, starting
from an initial thermal state, in direct analogy to the creation of an
entangled (Bell) state from an initially pure unentangled state. We identify
challenges and potential solutions to obtaining experimental gate fidelities
useful for quantum information processing in this type of system.
