The interaction of qubits via microwave frequency photons enables long-distance qubit- qubit coupling and facilitates the realization of a large-scale quantum processor. In various Current devices a strong coupling for semiconductor charge qubits and superconducting qubits to a microwave photon has been demonstrated. Although the qubits based on electron spins in semiconductor quantum dots comprise longer relevant coherence times for quantum applications, they have proven challenging to couple to microwave photons. In this theoretical work  we show that a sizable coupling for a single electron spin is possible via spin-charge hybridization using a magnetic field gradient in a silicon double quantum dot. Our analysis of the hybrid system consisting of a double quantum dot coupled to a microwave cavity confirms that, with the recent advances in silicon double quantum dots fabrication and control, spin-photon coupling with a sufficiently low spin decoherence rate is achievable with this setup, potentially allowing the strong-coupling regime. Based on parameters already shown in recent experiments, we predict optimal working points to achieve a coherent spin-photon coupling. Our predictions are in good agreement with recent measurements [2,3] which demonstrate strong coupling with spin-photon coupling rates of more than 10 MHz and cavity-based readout of the spin qubit. These results open a direct path towards entangling single spins using microwave frequency photons.
 M. Benito, X. Mi, J. M. Taylor, J. R. Petta, and G. Burkard,
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 X. Mi, M. Benito, J. M. Taylor, G. Burkard, and J. R. Petta, Nature 555, 599 (2018).
 N. Samkharadze, G. Zheng, N. Kalhor, D. Brousse, A. Sammak , U. C. Mendes, A.
Blais, G. Scappucci, and L. M. K. Vandersypen, Science 359, 1123 (2018). . Vandersypen, Science 359, 1123 (2018).