标题： 确定六方氮化硼中硼空位退相干抑制的最佳磁场配置 显示英文标题

标题： Identifying optimal magnetic field configurations for decoherence mitigation of boron vacancies in hexagonal boron nitride

摘要： 二维六方氮化硼中的负电荷硼空位中心已成为一种有前景的量子传感器。 然而，由于环境中的普遍存在核自旋，其灵敏度受到限制。 这些核自旋与中心电子自旋超精细耦合，有效地作为磁场波动器，导致快速退相干。 在这里，我们探讨静态磁场强度和方向在实现特殊子空间方面的有效性，这些子空间可能导致增强的自旋相干性。 具体来说，通过详细的自旋哈密顿量数值模拟，我们确定了特定的场配置，这些配置可以最小化能量梯度，因此预计能够促进退相干抑制。 我们还开发了一个基于微扰理论的近似解析模型，该模型准确预测了与电子自旋量子化轴对齐的磁场的低梯度子空间，不仅适用于硼空位，也适用于任何与附近核自旋耦合的自旋-1电子系统。 此外，为了激发实验验证，我们估算了各种偏置场配置下的相干寿命，并证明在某些区域确实可以实现显著的退相干抑制。 这些发现和所开发的方法为在低场范围内减轻退相干提供了有价值的见解。 显示英文摘要

摘要： The negatively charged boron vacancy center in 2D hexagonal boron nitride has emerged as a promising quantum sensor. However, its sensitivity is constrained due to ubiquitous nuclear spins in the environment. The nuclear spins, hyperfine coupled with the central electron spin, effectively behave as magnetic field fluctuators, leading to rapid decoherence. Here, we explore the effectiveness of static magnetic field strength and orientation in realizing peculiar subspaces that can lead to enhanced spin coherence. Specifically, using detailed numerical simulations of the spin Hamiltonian, we identify specific field configurations that minimize energy gradients and, consequently, are expected to facilitate decoherence suppression. We also develop an approximate analytical model based on the perturbation theory that accurately predicts these low-gradient subspaces for magnetic fields aligned with the electron spin quantization axis, applicable not only to boron vacancies but to any spin-1 electronic system coupled to nearby nuclear spins. Furthermore, to stimulate experimental validation, we estimate coherence lifetimes as a function of various bias field configurations and demonstrate that significant decoherence suppression can indeed be achieved in certain regions. These findings and the developed methodology offer valuable insights for mitigating decoherence in a low-field regime.