论文标题
在平行方案下多参数量子磁力测定法的最终精度
Ultimate precision of multi-parameter quantum magnetometry under the parallel scheme
论文作者
论文摘要
磁场的精确测量是量子计量学中最基本和最重要的任务之一。尽管在过去的几十年中已经对量子磁力测定法进行了广泛的研究，但对于估算磁场的所有三个组成部分，在平行方案下具有纠缠探针状态的所有三个组件可以达到最终精度。在这里，我们介绍了在平行方案下对磁场的所有三个组件的估计中的任意加权方差之和的最终下限，并表明对于足够大的N可以实现此下限。最佳的纠缠探针状态也可以明确构建实现最终精度的最佳纠缠探针状态。获得的精度设置了在平行方案下多参数量子磁力测定法的最终极限，这在量子计量学中具有基本的兴趣和重要性。我们的方法还提供了一种表征在探针状态的约束的多个参数的精度之间表征权衡的方法。
The precise measurement of a magnetic field is one of the most fundamental and important tasks in quantum metrology. Although extensive studies on quantum magnetometry have been carried out over past decades, the ultimate precision that can be achieved for the estimation of all three components of a magnetic field with entangled probe states under the parallel scheme remains unknown. Here we present the ultimate lower bound for the sum of arbitrarily weighted variances in the estimation of all three components of a magnetic field under the parallel scheme and show that this lower bound can be achieved for sufficiently large N. The optimal entangled probe state that achieves the ultimate precision is also explicitly constructed. The obtained precision sets the ultimate limit for the multi-parameter quantum magnetometry under the parallel scheme, which is of fundamental interest and importance in quantum metrology. Our approach also provides a way to characterize the tradeoff among the precisions of multiple parameters that arise from the constraints on the probe states.
