Quantum storage of photonic entanglement in a crystal
Quantum storage of photonic entanglement in a crystal
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DOI：
10.1038/nature09662
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发表时间：
2011-01-27
期刊：
影响因子：
64.8
通讯作者：
Gisin, Nicolas
中科院分区：
文献类型：
--
作者：
Clausen, Christoph;Usmani, Imam;Gisin, Nicolas
纠缠是量子物理学的基本特征，许多实验都致力于在不同的物理系统之间利用它。特别是，光和材料系统之间的纠缠是有趣的，因为它们在量子信息技术（如量子中继器（1-3）和量子网络(4)）中各自作为“飞行”和静止量子比特的角色。在这里，我们报告了在通信波长（1338 nm）的光子与存储在晶体中的单个集体原子激发之间的纠缠的演示。来自能量时间纠缠对(5)的一个光子被映射到晶体上，然后在预定的存储时间后释放到定义良好的空间模式中。另一个（电信波长）光子通过50米长的光纤链路直接发送到分析仪。通过对clauser - horn - shimony - holt不等式(6)几乎三个标准差（S=2.64 +/- 0.23）的违反，证明了晶体中纠缠态的成功存储。这些结果代表了基于固态器件的量子通信技术的重要一步。特别是，我们的资源为构建用于长距离量子网络的多路复用量子中继器(7)铺平了道路。
Entanglement is the fundamental characteristic of quantum physics-much experimental effort is devoted to harnessing it between various physical systems. In particular, entanglement between light and material systems is interesting owing to their anticipated respective roles as 'flying' and stationary qubits in quantum information technologies (such as quantum repeaters(1-3) and quantum networks(4)). Here we report the demonstration of entanglement between a photon at a telecommunication wavelength (1,338 nm) and a single collective atomic excitation stored in a crystal. One photon from an energy-time entangled pair(5) is mapped onto the crystal and then released into a well-defined spatial mode after a predetermined storage time. The other (telecommunication wavelength) photon is sent directly through a 50-metre fibre link to an analyser. Successful storage of entanglement in the crystal is proved by a violation of the Clauser-Horne-Shimony-Holt inequality(6) by almost three standard deviations (S=2.64 +/- 0.23). These results represent an important step towards quantum communication technologies based on solid-state devices. In particular, our resources pave the way for building multiplexed quantum repeaters(7) for long-distance quantum networks.