AI 中文总结
该研究针对单参数相位估计，证明基于高斯资源产生的 heralded 非高斯态的有效量子费舍尔信息不超过原始高斯输入的量子费舍尔信息，凸显量子传感中资源计数的重要性。
AI 中文摘要
非高斯态在量子传感中可展现出大的量子费舍尔信息（QFI）。然而在光学系统中，其产生常通过玻色采样型条件操作概率性实现，因此产生率受限。在评估传感性能时，必须考虑这种非高斯资源的概率性产生。由此自然产生一个问题：在量子传感中，使用 heralded 概率性非高斯态是否优于原始确定性高斯态？本文针对单参数相位估计回答该问题。利用无源线性光学系统中的光子数守恒，我们证明参数编码前的 heralded 态制备可映射为相位估计中参数编码后的后选择问题，该映射可将 heralding 的成功概率自然纳入计量性能。我们引入有效量子费舍尔信息（EQFI），其定义为 heralded 输出的成功概率加权 QFI，并证明其无法超过原始高斯输入的 QFI。该结果凸显了量子传感中资源计数的重要性，有助于更好理解光学量子传感的资源高效优势。
英文摘要
Non-Gaussian states can exhibit large quantum Fisher information (QFI) in quantum sensing. In optical systems, however, its generation is often probabilistic via the boson-sampling type conditional operation and thus its generation rate is limited. This probabilistic generation of non-Gaussian resource should be taken into account for evaluation of the sensing performance. Then a natural question arising is whether the use of heralded probabilistic non-Gaussian states is better than that of the original deterministic Gaussian states for quantum sensing. In this paper, we answer to this question for single-parameter phase-estimation. By using photon-number conservation in passive linear optical systems, we show that heralded state preparation before parameter encoding can be mapped to a postselection problem after parameter encoding for phase estimation. This mapping allows the success probability of heralding to be included naturally in the metrological performance. We introduce an effective quantum Fisher information (EQFI), defined as the success-probability-weighted QFI of the heralded outputs, and prove that it cannot exceed the QFI of the original Gaussian inputs. The result highlights the importance of resource counting in quantum sensing toward better understanding of the resource efficient advantage of optical quantum sensing.
