Mechanism behind disappearance and reappearance of single-shot fluctuations

Determine whether the intermittent disappearance and reappearance of single-shot spin readout fluctuations in the cavity transmission are caused by spectral diffusion of the silicon-vacancy center optical transition or ionization into a dark charge state under the applied pump/repump sequence.

Background

In single-shot readout experiments, the authors observed that the fluctuations associated with spin thermalization occasionally disappear and reappear during data acquisition. This behavior undermines state discrimination and complicates interpretation of spin dynamics.

The authors note potential causes such as spectral diffusion or ionization into a dark charge state, and hypothesize the green repump pulse may influence the charge environment. Disentangling these mechanisms is essential to stabilize single-shot performance and improve readout fidelity.

References

Another notable feature of the data is that the fluctuations due to the spin thermalization (i.e. single-shot readout) can be clearly observed to disappear and reappear at different points throughout the measurement. It is not clear if this is due to spectral diffusion or ionization into a dark charge state.

— A scalable gallium-phosphide-on-diamond spin-photon interface  (2601.04733 - Yama et al., 8 Jan 2026) in Section SI.3, Subsection "Single-shot readout"