Strong magnetic coupling between an electronic spin qubit and a mechanical resonator

We describe a technique that enables a strong coherent coupling between a single electronic spin qubit associated with a nitrogen-vacancy impurity in diamond and the quantized motion of a magnetized nanomechanical resonator tip. This coupling is achieved via careful preparation of dressed spin states which are highly sensitive to the motion of the resonator but insensitive to perturbations from the nuclear-spin bath. In combination with optical pumping techniques, the coherent exchange between spin and motional excitations enables ground-state cooling and controlled generation of arbitrary quantum superpositions of resonator states. Optical spin readout techniques provide a general measurement toolbox for the resonator with quantum limited precision.