  We propose a mechanism of coherent coupling between distant spin qubits
interacting dipolarly with a ferromagnet. We derive an effective two-spin
interaction Hamiltonian and estimate the coupling strength. We discuss the
mechanisms of decoherence induced solely by the coupling to the ferromagnet and
show that there is a regime where it is negligible. Finally, we present a
sequence for the implementation of the entangling CNOT gate and estimate the
corresponding operation time to be a few tens of nanoseconds. A particularly
promising application of our proposal is to atomistic spin-qubits such as
silicon-based qubits and NV-centers in diamond to which existing coupling
schemes do not apply.
