Experimental Ten-Photon Entanglement

Abstract

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 $\sim 12\mathrm{MHz}/\mathrm{W}$, a collection efficiency of $\sim 70\%$, and an indistinguishability of $\sim 91\%$ 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.