论文标题
两光子纠缠的一光子测量
One-photon measurement of two-photon entanglement
论文作者
论文摘要
纠缠是量子力学的基本特征，被认为是量子信息处理中的关键资源。测量纠缠是在广泛的应用和基础量子实验中的重要步骤。当两个粒子量子状态不是纯净的时，测量纠缠的标准方法需要检测两个颗粒。我们介绍了一种方法，其中仅需要检测其中一个颗粒来表征两粒子混合状态的纠缠。我们的方法基于量子干扰的原理。我们使用两个相同的两光子混合状态的来源，并生成一组单光子干扰模式。两光子量子状态的纠缠以干扰模式的可见性为特征。因此，我们的实验为验证和测量纠缠开辟了一个不同的途径，即使无法检测到这对中的一个粒子，也可以允许混合状态纠缠。
Entanglement is a fundamental feature of quantum mechanics, considered a key resource in quantum information processing. Measuring entanglement is an essential step in a wide range of applied and foundational quantum experiments. When a two-particle quantum state is not pure, standard methods to measure the entanglement require detection of both particles. We introduce a method in which detection of only one of the particles is required to characterize the entanglement of a two-particle mixed state. Our method is based on the principle of quantum interference. We use two identical sources of a two-photon mixed state and generate a set of single-photon interference patterns. The entanglement of the two-photon quantum state is characterized by the visibility of the interference patterns. Our experiment thus opens up a distinct avenue for verifying and measuring entanglement, and can allow for mixed state entanglement characterization even when one particle in the pair cannot be detected.
