Ten-Second Electron-Spin Coherence in Isotopically Engineered Diamond

Quantum Physics [Submitted on 8 Apr 2026] Ten-Second Electron-Spin Coherence in Isotopically Engineered Diamond Takashi Yamamoto, H. Benjamin van Ommen, Kai-Niklas Schymik, Beer de Zoeten, Shinobu Onoda, Seiichi Saiki, Takeshi Ohshima, Hadi Arjmandi-Tash, René Vollmer, Tim H. Taminiau Solid-state spin defects are a promising platform for quantum networks. A key requirement is to combine long ground-state spin-coherence times with a coherent optical transition for spin-photon entanglement. Here, we investigate the spin and optical coherence of single nitrogen-vacancy (NV) centres in (111)-grown isotopically engineered diamond. Our diamond-growth process yields a precisely controlled ^{13}\mathrm{C} concentration and low-ppb nitrogen concentrations. Combined with the mitigation of 50 Hz noise using a real-time feedforward scheme and tailored decoupling sequences, this enables record defect-electron-spin coherence times of T_2 = 6.8(1) ms for a Hahn echo and of T_2^{DD} = 11.2(8) s under dynamical decoupling. In addition, we observe coherent optical transitions with a near-lifetime-limited homogeneous linewidth of 16.9(4) MHz and characterize the spectral diffusion dynamics. These results provide new avenues to investigate the incorporation of impurities in diamond and new opportunities for improved spin-qubit control for quantum networks and other quantum technologies. Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2604.07439 [quant-ph]   (or arXiv:2604.07439v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2604.07439 Focus to learn more Submission history From: H. Benjamin Van Ommen [view email] [v1] Wed, 8 Apr 2026 18:00:01 UTC (1,285 KB) Access Paper: HTML (experimental) view license Current browse context: quant-ph < prev   |   next > new | recent | 2026-04 References & Citations INSPIRE HEP NASA ADS Google Scholar Semantic Scholar Export BibTeX Citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Demos Related Papers About arXivLabs Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)