  In a full-scale quantum computer with a fault-tolerant architecture, having
scalable, long-range interaction between qubits is expected to be a highly
valuable resource. One promising method of achieving this is through the
light-matter interaction between spins in semiconductors and photons in
superconducting cavities. This paper examines the theory of both transverse and
longitudinal spin-photon coupling and their applications in the silicon
metal-oxide-semiconductor (SiMOS) platform. We propose a method of coupling
which uses the intrinsic spin-orbit interaction arising from orbital
degeneracies in SiMOS qubits. Using theoretical analysis and experimental data,
we show that the strong coupling regime is achievable in the transverse scheme.
We also evaluate the feasibility of a longitudinal coupling driven by an AC
modulation on the qubit. These coupling methods eschew the requirement for an
external micromagnet, enhancing prospects for scalability and integration into
a large-scale quantum computer.
