We’re Closer to a Quantum Internet
Twenty-five years ago, University of Innsbruck scientists provided the blueprints for a quantum repeater. Now, quantum physicists led by Ben Lanyon from the Department of Experimental Physics at the University of Innsbruck have succeeded in building the core parts of a quantum repeater—a fully functioning network node made with two single matter systems enabling entanglement creation with a photon at the standard frequency of the telecommunications network and entanglement swapping operations. The current results are in Physical Review Letters.
A quantum internet is a network of quantum computers that will send, compute and receive information encoded in quantum states. It will likely not replace our current internet but co-exist to solve specific types of problems.
Quantum networks connect quantum processors or quantum sensors, allowing tap-proof communication and high-performance distributed sensor networks. Between network nodes, quantum information is exchanged by photons traveling through optical waveguides. Over long distances, photon loss increases dramatically since quantum information cannot simply be copied and amplified.
The node consists of two calcium ions captured in an ion trap within an optical resonator and single photon conversion to the telecom wavelength. The scientists demonstrated quantum information transfer over a 50-kilometer-long optical fiber, with the quantum repeater placed halfway between starting and end points. They were able to calculate which improvements of this design would be necessary to make transmission over 800 kilometers possible, connecting Innsbruck to Vienna.