Strong Einstein-Podolsky-Rosen entanglement from a single squeezed light source
Strong Einstein-Podolsky-Rosen entanglement from a single squeezed light source
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DOI：
10.1103/physreva.83.052329
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发表时间：
2011-03
影响因子：
2.9
通讯作者：
T. Eberle;V. Handchen;J. Duhme;T. Franz;R. Werner;R. Schnabel
中科院分区：
文献类型：
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作者：
T. Eberle;V. Handchen;J. Duhme;T. Franz;R. Werner;R. Schnabel
爱因斯坦-珀多尔斯基-罗森(EPR)纠缠是一个比仅仅证明纠缠更苛刻的标准。我们从理论和实验上分析了在平衡分束器中通过压缩模和真空模混合实现的低资源的二体连续变量纠缠的产生，即所谓真空级纠缠的产生。我们发现要观测EPR纠缠，总的光学损耗必须小于$33.3$$%$。然而，在这种方案下，任意强的EPR纠缠通常是可能的。我们实现了1550美元nm的连续波压缩光，非经典噪声降低高达9.9美元分贝，这是迄今为止电信波长的最高值。使用两个相位控制的平衡零差探测器，我们观察到EPR协方差积为$0.502\ifmmood\pm\Else\TextPM\FI，其中$1$是临界值。讨论了强高斯纠缠的可行性及其在短距离光纤网络量子密钥分配中的应用。
Einstein-Podolsky-Rosen (EPR) entanglement is a criterion that is more demanding than just certifying entanglement. We theoretically and experimentally analyze the low-resource generation of bipartite continuous-variable entanglement, as realized by mixing a squeezed mode with a vacuum mode at a balanced beam splitter, i.e., the generation of so-called vacuum-class entanglement. We find that in order to observe EPR entanglement the total optical loss must be smaller than $33.3$ $%$. However, arbitrarily strong EPR entanglement is generally possible with this scheme. We realize continuous-wave squeezed light at $1550$ nm with up to $9.9$ dB of nonclassical noise reduction, which is the highest value at a telecom wavelength so far. Using two phase-controlled balanced homodyne detectors we observe an EPR covariance product of $0.502\ifmmode\pm\else\textpm\fi{}0.006l1$, where $1$ is the critical value. We discuss the feasibility of strong Gaussian entanglement and its application for quantum key distribution in a short-distance fiber network.