Simple Optics Make Quantum Relay
Researchers from the NASA-Caltech Jet Propulsion Laboratory have found a way to make a quantum repeater using ordinary optical equipment. Practical quantum repeaters could boost the reach of quantum cryptography systems, and eventually enable quantum networks. The device would allow for an exponential improvement in the distance quantum bits can be transmitted.
The challenge was finding a way to preserve entanglement, which links particle properties like polarization regardless of the distance between the particles.
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