Matsukevich D N, Kuzmich A
School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA.
Science. 2004 Oct 22;306(5696):663-6. doi: 10.1126/science.1103346.
We report on the coherent quantum state transfer from a two-level atomic system to a single photon. Entanglement between a single photon (signal) and a two-component ensemble of cold rubidium atoms is used to project the quantum memory element (the atomic ensemble) onto any desired state by measuring the signal in a suitable basis. The atomic qubit is read out by stimulating directional emission of a single photon (idler) from the (entangled) collective state of the ensemble. Faithful atomic memory preparation and readout are verified by the observed correlations between the signal and the idler photons. These results enable implementation of distributed quantum networking.
我们报道了从两能级原子系统到单光子的相干量子态转移。单光子（信号）与冷铷原子的双组分系综之间的纠缠被用于通过在合适的基下测量信号，将量子存储元件（原子系综）投影到任何期望的状态。通过从系综的（纠缠）集体态激发单光子（闲频光）的定向发射来读出原子量子比特。通过观察信号光子与闲频光光子之间的相关性，验证了可靠的原子存储制备和读出。这些结果使得分布式量子网络的实现成为可能。
