Wu, W., Davis, E. J., Hughes, L. B., Ye, B., Wang, Z., Kufel, D., Ono, T., Meynell, S. A., Block, M., Liu, C., Yang, H., Jayich, A. C. B., Yao, N. Y. (2025). Spin squeezing in an ensemble of nitrogen–vacancy centres in diamond. Nature. https://doi.org/10.1038/s41586-025-09524-8