Physicists entangle quantum memories across a record-breaking 420 km

Optical fibers are already the backbone of global communication systems. Recently, however, physicists have started to explore how their functionality could be boosted further by conveying information via entangled quantum particles—potentially enabling instantaneous exchanges of information across vast distances. Such a system could eventually be the basis of a future 'quantum internet,' offering a level of security and computing power beyond anything possible today.