Record-Setting Quantum Entanglement Connects Two Atoms Across 20 Miles

Researchers from two Germany universities 'have demonstrated quantum entanglement of two atoms separated by 33 km (20.5 miles) of fiber optics," reports New Atlas.

This is an important step on the way to realizing a practical quantum internet, according to the team. Two rubidium atoms were kept in optical traps in two different buildings on the Ludwig-Maximilians-UniversityMunich campus. They were separated by 700 m of fiberoptics, which was extended out to 33 km. Each atom was excited with a laser pulse, which causes it to emit a photon that is entangled with the atom. At the receiving station in the middle, the photons are sent down the fiberoptic cables. The two atoms become entangled with each other because they're both already entangled with their own atoms. This is the first time that two atoms have been entangled over a long distance.