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arXiv 2412.03383quant-phmath-phmath.MP
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利用真实与受限集体测量对三个平行自旋的最优估计

Optimal estimation of three parallel spins with genuine and restricted collective measurements

Changhao Yi, Kai Zhou, Zhibo Hou, Guo-Yong Xiang, Huangjun Zhu

AI总结:

本研究针对三平行自旋随机自旋态估计问题,推导了双可分测量的最大估计保真度解析公式,明确了其与真实集体测量的性能差距及最优双可分测量结构,揭示了量子测量领域的多体非经典性图景。

摘要:

与单独测量相比,对全同且独立的量子系统进行集体测量在信息提取方面具备优势。但在多体场景下,人们对受限集体测量与真实集体测量之间的区别仍知之甚少。本研究围绕一个简单且经典的估计问题——即给定三个平行自旋时对随机自旋态的估计——建立了严格的性能差距。值得注意的是,我们推导了双可分测量最大估计保真度的解析公式,并阐明了其与真实集体测量的保真度差距。此外,我们还厘清了最优双可分测量的结构。研究发现,最大估计保真度可通过单向(一个方向而非反向)通信辅助的双拷贝和单拷贝测量实现。本工作揭示了量子测量(而非量子态)中多体非经典性的丰富图景,有望推动后续研究。

英文摘要:

Collective measurements on identical and independent quantum systems can offer advantages in information extraction compared with individual measurements. However, little is known about the distinction between restricted collective measurements and genuine collective measurements in the multipartite setting. In this work we establish a rigorous performance gap based on a simple and old estimation problem, the estimation of a random spin state given three parallel spins. Notably, we derive an analytical formula for the maximum estimation fidelity of biseparable measurements and clarify its fidelity gap from genuine collective measurements. Moreover, we clarify the structure of optimal biseparable measurements. It turns out that the maximum estimation fidelity can be achieved by two- and one-copy measurements assisted by one-way communication in one direction, but not the other way. Our work reveals a rich landscape of multipartite nonclassicality in quantum measurements instead of quantum states and is expected to trigger further studies.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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