发表机构
Xi’an Jiaotong University（西安交通大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文建立统一框架，将隐蔽性作为资源约束，提出隐蔽性约束量子Fisher信息（CCQFI），证明TMSV探测在强隐蔽性下保持计量优势，而GCS失效，揭示隐蔽性决定量子目标传感的计量极限。
AI 中文摘要
量子隐蔽目标传感旨在检测嵌入热环境中的低反射率目标，同时避免被对手发现。这种隐蔽性要求限制了可允许的探测能量，从而在隐蔽性与传感性能之间施加了权衡。然而，这种资源约束如何决定目标参数的最终估计精度在很大程度上仍未得到探索。为填补这一空白，我们建立了一个统一框架，将隐蔽目标判别与量子增强参数估计联系起来。我们首先提出了微扰ε-隐蔽性引起的探测能量界限，该界限给出了以O(√(ε/M))速率收窄的可允许能量窗口。此外，我们引入了隐蔽性约束量子Fisher信息（CCQFI）来量化目标反射率估计的最终精度，并评估其通过特定测量的可达性。对于高斯分布相干态（GCS）和双模压缩真空（TMSV）探测，其CCQFI分别以O(ε)和O(M)+O(√(εM))+O(ε)的规模缩放。特别地，在强隐蔽性区域ε→0时，GCS CCQFI消失，而TMSV保留有限的O(M)贡献，展现出显著的计量学优势。此外，光子计数可饱和GCS CCQFI，而零差探测对TMSV探测实现了更高的可达性。我们的工作将隐蔽性识别为控制量子目标传感计量极限的定量资源约束。
英文摘要
Quantum covert target sensing aims to detect low-reflectivity targets embedded in the thermal environment while avoiding discovery by an adversary. This covertness requirement constrains the admissible probe energy, thereby imposing a trade-off between covertness and sensing performance. However, how this resource constraint determines the ultimate estimation precision of the target parameter remains largely unexplored. To fill this gap, we establish a unified framework connecting covert target discrimination with quantum-enhanced parameter estimation. We first present perturbative $ε$-covertness-induced bounds on the probe energy, which yield an admissible energy window narrowing as $\mathcal{O}(\sqrt{ε/M})$. Moreover, we introduce the covertness-constrained quantum Fisher information (CCQFI) to quantify the ultimate precision of target-reflectivity estimation and assess its attainability with specific measurements. For Gaussian-distributed coherent-state (GCS) and two-mode squeezed vacuum (TMSV) probes, their CCQFIs scale as $\mathcal{O}(ε)$ and $\mathcal{O}(M)+\mathcal{O}(\sqrt{εM})+\mathcal{O}(ε)$, respectively. In particular, in the strong covertness regime $ε\to0$, the GCS CCQFI vanishes, whereas the TMSV retains a finite $\mathcal{O}(M)$ contribution exhibiting a pronounced metrological advantage. Besides, photon counting saturates the GCS CCQFI, whereas homodyne detection achieves a higher attainability for the TMSV probe. Our work identifies covertness as a quantitative resource constraint governing the metrological limits of quantum target sensing.
Comments15 pages, 8 figures
