(ScientificAmerican) Quantum physicists want to build quantum networks sporting full-blown quantumness, where information is created, stored and moved around in ways provide a level of privacy, security and computational clout that is impossible to achieve with today’s internet. While a fully realized quantum network is still a far-off vision, recent breakthroughs in transmitting, storing and manipulating quantum information have convinced some physicists that a simple proof-of-principle is imminent.
Ben Lanyon of the Institute for Quantum Optics and Quantum Information in Innsbruck, Austria, believes such a network may be built in the next five years. Lanyon’s team is part of Europe’s Quantum Internet Alliance, coordinated by Stephanie Wehner at the Delft University of Technology in The Netherlands, which is tasked with creating a quantum network. Europe is competing with similar national efforts in China—which in 2016 launched Micius, a quantum communications satellite.
“The main feature of a quantum network is that you are sending quantum information instead of classical information,” says Delft University’s Ronald Hanson. Classical information deals in bits that have values of either 0 or 1. Quantum information, however, uses quantum bits, or qubits, which can be in a superposition of both 0 and 1 at the same time. Qubits are already being used for creating secret keys—random strings of 0s and 1s—that can then be used to encode classical information, an application called quantum key distribution (QKD).

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