Strong Spin-Photon Coupling in Silicon

Long coherence times of single spins in Silicon quantum dots make these systems highly attractive for quantum computation. A crucial missing ingredient for realization of large networks of quantum dot based spin qubits has been long range coherent interconnects between them.
We report strong coupling of a single electron spin trapped in a silicon double quantum dot and a single microwave photon stored in a 1.3 mm long on-chip high-impedance superconducting resonator. The electric field component of the cavity photon couples directly to the charge dipole of the electron in the double dot, and indirectly to the electron spin, through a local magnetic field gradient from a nearby micromagnet. We extract charge-photon coupling strength g_C>200 MHz, and spin-photon coupling strength 2g_S>30 MHz, well above the combined decoherence rates of the spin and the photon.
This result opens the way to cavity-mediated quantum gates between spin qubits at millimeter range, removing a major roadblock for the scalability of spin based quantum processors.