发表机构
Université libre de Bruxelles; International Iberian Nanotechnology Laboratory (INL); Center for Quantum Enabled-Computing, Center for Theoretical Physics of the Polish Academy of Sciences; Instituto de Física, Universidade Federal Fluminense（布鲁塞尔自由大学; 伊比利亚纳米技术实验室; 波兰科学院理论物理中心量子使能计算中心; 弗鲁米嫩塞联邦大学物理研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出两种高效实验协议，利用傅里叶干涉仪或随机线性光学干涉仪结合光子计数，以最优样本复杂度认证多光子不可区分性保真度，无需先验假设，基于Hong-Ou-Mandel测试的多光子推广，使严格认证成为可能。
AI 中文摘要
多光子不可区分性是光子量子技术的关键资源，然而其表征通常依赖于资源密集型方法。在本工作中，我们开发了两种高效且实验友好的协议，用于估计或界定N光子态与最近完美不可区分态的保真度$F_{\mathrm{ind}}$。第一种协议适用于制备可分态的光源，使用单个傅里叶干涉仪配合光子数分辨探测，并给出$F_{\mathrm{ind}}$的紧致双侧界限。第二种协议结合线性光学干涉仪的随机实现与光子计数，能够直接估计任意N光子态的$F_{\mathrm{ind}}$。两种协议都能以可证明最优的$\mathcal{O}(1/\epsilon)$样本量认证$F_{\mathrm{ind}} = 1 - \mathcal{O}(\epsilon)$，这与先前需要部分不可区分性模型先验假设的方法形成对比。我们的方法基于Hong-Ou-Mandel测试的多光子推广，使多光子不可区分性的严格且操作上有意义的认证在当前光子技术条件下成为可能。
英文摘要
Multiphoton indistinguishability is a key resource for photonic quantum technologies, yet its characterization typically relies on resource-intensive methods. In this work, we develop two efficient and experimentally friendly protocols to estimate or bound the fidelity $F_{\mathrm{ind}}$ of an $N$-photon state to the closest perfectly indistinguishable state. The first protocol applies to sources preparing separable states, uses a single Fourier interferometer together with photon-number-resolving detection, and yields tight two-sided bounds on $F_{\mathrm{ind}}$. The second protocol combines randomized implementations of linear-optical interferometers with photon counting, enabling direct estimation of $F_{\mathrm{ind}}$ for arbitrary $N$-photon states. Both protocols can certify $F_{\mathrm{ind}} = 1 - \mathcal{O}(ε)$ using provably optimal $\mathcal{O}(1/ε)$ samples, in contrast to previous approaches which required prior assumptions on the model of partial distinguishability. Our methods, based on a multiphoton generalization of the Hong-Ou-Mandel test, bring the rigorous and operationally meaningful certification of multiphoton indistinguishability within reach of current photonic technologies.
Comments25 pages, 2 figures
