Quantum metrology is a powerful tool for explorations of fundamental physical phenomena and applications in material science and biochemical analysis. While in principle the sensitivity can be improved by increasing the density of sensing particles, in practice this improvement is severely hindered by interactions between them. Here, using a dense ensemble of interacting electronic spins in diamond, we demonstrate a novel approach to quantum metrology to surpass such limitations. It is based on a new method of robust quantum control, which allows us to simultaneously suppress the undesired effects associated with spin-spin interactions, disorder, and control imperfections, enabling a fivefold enhancement in coherence time compared to state-of-the-art control sequences. Combined with optimal spin state initialization and readout directions, this allows us to achieve an ac magnetic field sensitivity well beyond the previous limit imposed by interactions, opening a new regime of high-sensitivity solid-state ensemble magnetometers.

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具有强相互作用的自旋系统的量子计量学

量子计量学是探索基本物理现象及其在材料科学和生化分析中的应用的强大工具。虽然原则上可以通过增加感测颗粒的密度来提高灵敏度，但实际上，这种改进由于它们之间的相互作用而受到严重阻碍。在这里，通过使用相互作用的钻石中的电子自旋的密集集合，我们展示了一种新颖的量子计量方法，可以超越这种局限性。它基于可靠的量子控制的新方法，该方法使我们能够同时抑制与自旋-自旋相互作用，无序和控制缺陷相关的不良影响，与最新技术相比，相干时间可提高五倍控制序列。结合最佳的自旋状态初始化和读出方向，