Such quantum information networks would be extremely secure and could also allow new quantum computers to work together to complete problems that are currently unsolvable. However, scientists currently designing these networks face several challenges, including how to preserve fragile quantum information over long distances.
In an article published in the journal Science, the researchers described how they were able to store and transmit bits of quantum information, known as qubits, using a diamond in which they had replaced two carbon atoms with one silicon atom.
In standard communications networks, devices called repeaters briefly store and re-transmit signals to allow them to travel greater distances. Nathalie de Leon, an assistant professor of electrical engineering at Princeton University and the lead researcher, said the diamonds could serve as quantum repeaters for networks based on qubits.
The idea of a quantum repeater has been around for a long time, "but nobody knew how to build them," de Leon said. "We were trying to find something that would act as the main component of a quantum repeater."
In order to create quantum repeaters a material needs to be found that could both store and transmit qubits. So far, the best way to transmit qubits is to encode them in particles of light, called photons. Optical fibers currently used across much of the network already transmit information via photons. However, qubits in an optical fiber can travel only short distances before their special quantum properties are lost and the information is scrambled. It is difficult to trap and store a photon, which by definition moves at the speed of light.