The measured nc,d overall approached the lower bound closely. References 1. Meter, R. V. Quantum Networking (Wiley-ISTE, 2014). 2. Kimble, H. J. The quantum internet. Nature 453, 1023–1030 (2008). 3. Blinov, B., Moehring, D., Duan, L. & Monroe, C. Observation of entanglement...