  We propose a novel architecture for scalable quantum computation based on
quantum actuated decoherence-free (DF) qubits. Each qubit is encoded by the DF
subspace of a nuclear spin pair and has long coherence time. A nitrogen-vacancy
center in diamond is chosen as the quantum actuator to realize initialization,
readout and universal control of DF qubits with fidelities higher than 99%. It
reduces the challenge of classical interfaces from controlling and observing
complex quantum systems down to a simple quantum actuator. Our scheme also
provides a novel way to handle complex quantum systems.
