Theory of spin-orbit mediated hole spin-photon coupling in lateral Ge/SiGe quantum dots*

Coupling semiconductor spin qubits to microwave photons enables long-range quantum information transfer, and strong spin-photon coupling has recently been demonstrated for electron spin qubits in silicon [1, 2]. In this context, hole spin qubits in lateral Ge/SiGe quantum dots [3, 4] represent an attractive alternative platform without valley degeneracy and with strong intrinsic spin-orbit interaction. We present an analytical formulation of heavy hole spin-photon coupling mediated by spin-orbit interaction in lateral Ge/SiGe quantum dots. Using this formalism, we derive expressions for effective single-photon and three-photon coupling within this system and explore the strengths of these interactions in experimentally relevant parameter regimes.

[1] X. Mi et al., Nature 555, 599 EP (2018).
[2] N. Samkharadze et al., Science 359, 1123 (2018).
[3] W. J. Hardy et al., Nanotechnology 30, 215202 (2019).
[4] A. Hofmann et al., arXiv:1910.05841 (2019).