Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
Nature. 2010 Aug 5;466(7307):730-4. doi: 10.1038/nature09256.
Quantum entanglement is among the most fascinating aspects of quantum theory. Entangled optical photons are now widely used for fundamental tests of quantum mechanics and applications such as quantum cryptography. Several recent experiments demonstrated entanglement of optical photons with trapped ions, atoms and atomic ensembles, which are then used to connect remote long-term memory nodes in distributed quantum networks. Here we realize quantum entanglement between the polarization of a single optical photon and a solid-state qubit associated with the single electronic spin of a nitrogen vacancy centre in diamond. Our experimental entanglement verification uses the quantum eraser technique, and demonstrates that a high degree of control over interactions between a solid-state qubit and the quantum light field can be achieved. The reported entanglement source can be used in studies of fundamental quantum phenomena and provides a key building block for the solid-state realization of quantum optical networks.
量子纠缠是量子理论中最令人着迷的方面之一。纠缠的光光子现在被广泛用于量子力学的基本测试和量子密码学等应用。最近的几项实验证明了光光子与被俘获的离子、原子和原子团的纠缠，这些原子团被用于连接分布式量子网络中的远程长期记忆节点。在这里，我们实现了单个光光子的偏振与金刚石中单个氮空位中心的单个电子自旋相关的固态量子位之间的量子纠缠。我们的实验纠缠验证使用了量子擦除技术，并证明了可以实现对固态量子位与量子光场之间相互作用的高度控制。所报道的纠缠源可用于研究基本的量子现象，并为固态量子光学网络的实现提供了关键构建块。
