Entanglement Sent Over 50 km of Optical Fiber

(Phys.org) The team of physicist Ben Lanyon at the Department of Experimental Physics at the University of Innsbruck and at the Institute of Quantum Optics and Quantum Information of the Austrian Academy of Sciences has achieved a record for the transfer of quantum entanglement between matter and light. For the first time, a distance of 50 kilometers was covered using fiber optic cables. “This is two orders of magnitude further than was previously possible and is a practical distance to start building inter-city quantum networks,” said Lanyon.
Lanyon and his team show that their methods would enable entanglement to be generated between ions 100 kilometers apart and more. With 100-kilometer node spacing now a possibility, one could therefore envisage building the world’s first intercity light-matter quantum network in the coming years: only a handful of trapped ion-systems would be required on the way to establish a quantum internet between Innsbruck and Vienna, for example.
Lanyon’s team is part of the Quantum Internet Alliance, an international project within the Quantum Flagship framework of the European Union.