Goebel Alexander M, Wagenknecht Claudia, Zhang Qiang, Chen Yu-Ao, Chen Kai, Schmiedmayer Jörg, Pan Jian-Wei
Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 12, 69120 Heidelberg, Germany.
Phys Rev Lett. 2008 Aug 22;101(8):080403. doi: 10.1103/PhysRevLett.101.080403. Epub 2008 Aug 21.
We report an experimental demonstration of entanglement swapping over two quantum stages. By successful realizations of two cascaded photonic entanglement swapping processes, entanglement is generated and distributed between two photons, that originate from independent sources and do not share any common past. In the experiment we use three pairs of polarization entangled photons and conduct two Bell-state measurements: one between the first and second pair, and one between the second and third pair. This results in projecting the remaining two outgoing photons from pair 1 and 3 into an entangled state, as characterized by an entanglement witness. The experiment represents an important step towards a full quantum repeater where multiple entanglement swapping is a key ingredient.
我们报告了在两个量子阶段上进行纠缠交换的实验演示。通过成功实现两个级联的光子纠缠交换过程，纠缠在两个源自独立源且没有任何共同过去的光子之间产生并分布。在实验中，我们使用三对偏振纠缠光子并进行两次贝尔态测量：一次在第一对和第二对之间，另一次在第二对和第三对之间。这导致将来自第1对和第3对的其余两个出射光子投影到一个纠缠态，这由一个纠缠见证者来表征。该实验是迈向完整量子中继器的重要一步，其中多次纠缠交换是关键要素。
