内容：

Speaker: Wei Chang (常炜)

Paper : Storing a single photon as a spin wave entangled with a flying photon in the telecommunication bandwidth

Authors:  Wei Zhang, Dong-Sheng Ding, Shuai Shi, Yan Li, Zhi-Yuan Zhou, Bao-Sen Shi, and Guang-Can Guo

Reference: Phys. Rev. A 93, 022316 (2016)

Abstract：

Quantum memory is an essential building block for quantum communication and scalable linear quantum
computation. Storing two-color entangled photons with one photon being at the telecommunication (telecom)
wavelength while the other photon is compatible with quantum memory has great advantages toward the realization
of the fiber-based long-distance quantum communicationwith the aid of quantum repeaters. Here, we report an
experimental realization of storing a photon entangled with a telecom photon in polarization as an atomic spinwave
in a cold atomic ensemble, thus establishing the entanglement between the telecom-band photon and the atomicensemble memory in a polarization degree of freedom. The reconstructed density matrix and the violation of the Clauser-Horne-Shimony-Holt inequality clearly show the preservation of quantum entanglement during storage.
Our result is very promising for establishing a long-distance quantum network based on cold atomic ensembles.