Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Phys Rev Lett. 2019 Oct 4;123(14):140504. doi: 10.1103/PhysRevLett.123.140504.
Entanglement between a single photon and a matter qubit is an indispensable resource for quantum repeater and quantum networks. With atomic ensembles, the entanglement creation probability is typically very low to inhibit high-order events. In this paper, we propose and experimentally realize a scheme that creates atom-photon entanglement with an intrinsic efficiency of 50%. We make use of Rydberg blockade to generate two collective excitations, lying in separate internal states. By introducing the momentum degree of freedom for the excitations, and interfering them via Raman coupling, we entangle the two excitations. Via retrieving one excitation, we create the entanglement between the polarization of a single photon and the momentum of the remaining atomic excitation, with a measured fidelity of 0.901(8). The retrieved optical field is verified to be genuine single photons. The realized entanglement may be employed to create entanglement between two distant nodes in a fully heralded way and with a much higher efficiency.
单光子与物质量子比特的纠缠是量子中继器和量子网络不可或缺的资源。在原子集合中，纠缠的产生概率通常非常低，以抑制高阶事件。在本文中，我们提出并实验实现了一种具有 50%固有效率的原子-光子纠缠生成方案。我们利用里德堡阻塞来产生两个集体激发，它们处于不同的内部状态。通过引入激发的动量自由度，并通过拉曼耦合对它们进行干涉，我们将两个激发纠缠在一起。通过检索一个激发，我们在单个光子的偏振和剩余原子激发的动量之间创建纠缠，测量保真度为 0.901(8)。检索到的光场被验证为真正的单光子。实现的纠缠可以用于以更高的效率以完全标记的方式在两个远程节点之间创建纠缠。
