Quantum networks offer a way to overcome the size and complexity limitations of single quantum devices by linking multiple nodes into a scalable architecture. Group-IV color centers in diamond, paired with long-lived nuclear spins, have emerged as promising building blocks demonstrating proof-of-concept experiments such as blind quantum computing and quantum-enhanced sensing. However, realizing a large-scale electro-nuclear register remains a major challenge. Here we establish the germanium-vacancy (GeV) center as a viable platform for such network nodes. Using correlation spectroscopy, we identify single nuclear spins within a convoluted spin environment, overcoming limitations imposed by the color center's spin-1/2 nature and thereby enabling indirect control of these nuclear spins. We further demonstrate high-fidelity single-shot readout of both the GeV center (95.8%) and a neighboring 13C nuclear spin (93.7%), a key tool for feed-forward error correction. These critical advances position the GeV center as a compelling candidate for next-generation quantum network nodes.
@article{arxiv.2510.09164,
title = {High-Fidelity Single-Shot Readout and Selective Nuclear Spin Control for a Spin-1/2 Quantum Register in Diamond},
author = {Prithvi Gundlapalli and Philipp J. Vetter and Genko Genov and Michael Olney-Fraser and Peng Wang and Matthias M. Müller and Katharina Senkalla and Fedor Jelezko},
journal= {arXiv preprint arXiv:2510.09164},
year = {2025}
}