A quantum spin transducer based on nanoelectromechanical resonator arrays

Isolated electronic and nuclear spins in solids are at present being actively explored for potential quantum-computing applications. Spin degrees of freedom provide an excellent quantum memory, owing to their weak magnetic interactions with the environment. For the same reason, however, it is difficult to achieve controlled interactions of spins over distances larger than tens of nanometres. Here we propose a new realization of a quantum data bus for spin qubits where spins are coupled to the motion of magnetized mechanical resonators through magnetic-field gradients. Provided that the mechanical system is charged, the magnetic moments associated with spin qubits can be effectively amplified to enable a coherent spin-spin coupling over long distances through Coulomb forces. Our approach is applicable to a wide class of electronic spin qubits, which can be localized near magnetized tips and can be used for the implementation of hybrid quantum-computing architectures.