标题： 增强纠缠的纳米级单自旋传感 显示英文标题

标题： Entanglement-Enhanced Nanoscale Single-Spin Sensing

摘要： 检测单个自旋——包括稳定态和亚稳态——代表了量子传感领域的一个基础性挑战，在凝聚态物理、量子化学以及单分子磁共振成像等领域有着广泛的应用。 尽管金刚石中的氮-空位（NV）中心已成为强大的纳米级传感器，但它们在单自旋探测方面的性能仍然受到显著环境噪声和受限的探测体积的制约。 在这里，我们提出并展示了通过使用纠缠的NV对来克服这些限制的纠缠增强传感协议。 与环境条件下单独的NV中心相比，我们的方法在灵敏度上提高了3.4倍，并且在空间分辨率上减少了1.6倍。 该协议采用精心设计的纠缠态，通过量子干涉放大目标自旋信号同时抑制环境噪声。 关键的是，我们将这些能力扩展到解析亚稳态单自旋动力学，通过识别状态相关的耦合强度直接观察不同自旋状态之间的随机跃迁。 这种双重功能能够同时检测静态和动态自旋物种，用于研究复杂的量子系统。 所实现的性能确立了纠缠增强传感作为一种可行的方法，朝着量子材料和界面的原子尺度表征迈进。 显示英文摘要

摘要： Detecting individual spins--including stable and metastable states--represents a fundamental challenge in quantum sensing with broad applications across condensed matter physics, quantum chemistry, and single-molecule magnetic resonance imaging. While nitrogen-vacancy (NV) centers in diamond have emerged as powerful nanoscale sensors, their performance for single-spin detection remains constrained by substantial environmental noise and restricted sensing volume. Here, we propose and demonstrate an entanglement-enhanced sensing protocol that overcomes these limitations through the strategic use of entangled NV pairs. Our approach achieves a 3.4-fold enhancement in sensitivity and a 1.6-fold reduction in spatial resolution relative to single NV centers under ambient conditions. The protocol employs carefully engineered entangled states that amplify target spin signals through quantum interference while suppressing environmental noise. Crucially, we extend these capabilities to resolve metastable single-spin dynamics, directly observing stochastic transitions between different spin states by identifying state-dependent coupling strengths. This dual functionality enables simultaneous detection of static and dynamic spin species for studying complex quantum systems. The achieved performance establishes entanglement-enhanced sensing as a viable pathway toward atomic-scale characterization of quantum materials and interface.