Not long ago, a reporter learned from the University of Science and Technology of China that Pan Jianwei, a professor at the university, and colleagues Chen Yuao and Zhao Bo recently used parametric down-conversion light sources to realize nested entanglement purification and secondary entanglement exchange in quantum repeaters based on linear optics Process for the future to achieve atomic-based scalable linear optical quantum repeater provides a forward-looking technical guidance. The two international academic journals Nature Photonics and Physical Review Letters recently published these two achievements respectively. Quantum communications on the ground will be affected by link attenuation and noise, and need to use quantum repeaters to achieve long-distance communications. Since the concept was proposed in 1998, scientists have been working on the road to building a practical quantum repeater. Pan Jianwei team is a world leader in the preparation and manipulation of multiphoton entanglement. Recently, they demonstrated for the first time the nested quantum entanglement purification and cascade quantum entanglement exchange based on the eight-body entangled light source. By ingeniously setting the Beier state measurement device, the two-photon interference term in the entanglement exchange process can be completely eliminated, and the further controllability of the distribution quantum state is retained. The optical demonstration of a scalable quantum repeater was successfully implemented using a combination of fiber analog quantum storage and measurement feedback. These two work break through the technical obstacles that can only demonstrate a single entanglement manipulation in quantum repeaters in the past. For the first time, continuous entanglement control of the quantum states is achieved, and scalable quantum repeater technology is developed based on the linear optical system. Reviewers of Nature Photonics and Physical Review Letters commented highly on both outcomes, with experimental implementation of nested purification being hailed as a "heroic experiment." Water Treatment,Siliphos Ball,Sodium Metasilicate Anhydrous,Caustic Soda Pearls Tianjin Centerstar Chemical Co., LTD. , https://www.tccadmixture.com