(Phys.org) Physicists at Ludwig Maximilian University of Munich together with colleagues at Saarland University, have successfully demonstrated the transport of an entangled state between an atom and a photon via an optic fiber over a distance of up to 20 km—thus setting a new record and paving the way for quantum networks.
The entangled state of an atom and a photon can be transmitted via an optic fiber (like those used in telecommunications networks) over a distance of up to 20 km. The previous record was 700 meters. “The experiment represents a milestone, insofar as the distance covered confirms that quantum information can be distributed on a large scale with little loss,” says Weinfurter. “Our work therefore constitutes a crucial step toward the future realization of quantum networks.”
In the next step, the researchers plan to frequency convert the light emitted by a second atom, which should enable them to generate entanglement between the two atoms over long telecommunications fibers. In the event of success, field experiments will be undertaken also adding new nodes to a growing network.