Miles ahead: China team boosts atom entanglement distance record fourfold

Chinese scientists have achieved the quantum entanglement of cold atoms across a record-breaking 420km (260 miles), a breakthrough they say lays the groundwork for intercity quantum networks.
According to a paper published by the peer-reviewed journal Physical Review Letters on August 11, the distance was more than four times previous demonstrations and exceeded the threshold at which direct transmission encounters fundamental physical limits.
“Our experiment provides a test bed for studying...