For the first time, a team at University of Innsbruck, has sent a photons entangled with matter over 50 km of optical fiber. This paves the way for the practical use of quantum networks and sets a milestone for a future quantum internet.
The quantum internet: secure communications, powerful distributed sensor networks, the ultimate in band compression. An exciting future to be sure, but quantum information cannot be copied, so it is not possible to send this information over a classical network. Quantum information must be transmitted using quantum particles and special interfaces for detection. The Innsbruck experiment is attempting to control both the transmission of try quantum particle as well as the interfaces that are used to read the information. The work was done at the Department of Experimental Physics at the University of Innsbruck together with the Institute of Quantum Optics and Quantum Information of the Austrian Academy of Sciences and it set a record for the transfer of quantum entanglement between matter and light. A transmission of 50 kilometers was achieved using fiber optic cables.
Dr. Ben Lanyon, the lead scientist, was awarded the Austrian START Prize in 2015
"This is two orders of magnitude further than was previously possible and is a practical distance to start building inter-city quantum networks," says Ben Lanyon.
V. Krutyanskiy, M. Meraner, J. Schupp, V. Krcmarsky, H. Hainzer, B. P. Lanyon. Light-matter entanglement over 50 km of optical fibre. npj Quantum Information, 2019; 5 (1) DOI: 10.1038/s41534-019-0186-3