To sustain delicate light-based quantum states over a continental scale, fiber-based networks will need quantum repeaters. These devices rely on a protocol known as entanglement swapping, which iteratively transfers entanglement from one pair of photons to another pair in the next segment. This process requires each segment to be equipped with a quantum memory, and consecutive memories must be synchronized. Now Alberto E. Rodriguez-Moldes of the Institute of Photonic Sciences (ICFO) in Spain and colleagues have demonstrated a long-lived quantum memory that could enable synchronized operations in a network of widely separated nodes.
To read more, click here.