Theory on spectral diffusion and electrically driven interferometry of qubits

Scalable spin-to-photon interfaces require quantum emitters with strong optical-transition dipole moment and low coupling to phonons and stray electric fields. Here, we show that inversion symmetry is not a prerequisite criterion for a spectrally stable quantum emitter. We find that identical electron density in ground and excited states can eliminate the coupling to the stray electric fields. We demonstrate this effect on silicon-vacancy qubit in silicon carbide by first principles methods (SiC) [1,2]. Our study opens an additional rationale in seeking promising materials towards the realization of robust spin-to-photon interfaces. Furthermore, we show by density functional theory that low-symmetry of defects can provide coherent optical and spin subsystems that can be harnessed to achieve electrically driven interferometry of SiC divacancy qubits [3].

[1] P. Udvarhelyi et al., Phys. Rev. Appl. 11, 044022 (2019)
[2] R. Nagy et al., Nat. Commun. 10 1954 (2019)
[3] K. C. Miao et al., arXiv:1905.12780, accepted to Science Advances