||Xi-Lin Wang, Luo-Kan Chen, W. Li, H.-L. Huang, C. Liu, C. Chen, Y.-H. Luo, Z.-E. Su, D. Wu, Z.-D. Li, H. Lu, Y. Hu, X. Jiang, C.-Z. Peng, L. Li, N.-L. Liu, Yu-Ao Chen, Chao-Yang Lu, and Jian-Wei Pan
||We report the first experimental demonstration of quantum entanglement among ten spatially separated single photons. A near-optimal entangled photon-pair source was developed with simultaneously a source brightness of ∼12 MHz/W, a collection efficiency of ∼70%, and an indistinguishability of ∼91% between independent photons, which was used for a step-by-step engineering of multiphoton entanglement. Under a pump power of 0.57 W, the ten-photon count rate was increased by about 2 orders of magnitude compared to previous experiments, while maintaining a state fidelity sufficiently high for proving the genuine ten-particle entanglement. Our work created a state-of-the-art platform for multiphoton experiments, and enabled technologies for challenging optical quantum information tasks, such as the realization of Shor’s error correction code and high-efficiency scattershot boson sampling.