High-fidelity, long-distance teleportation paves way for quantum internet
A quantum internet would be much faster and more secure than the one you’re using right this second – and now such a network may be one step closer to reality. Scientists have used quantum teleportation to send information over long distances, with a higher fidelity than ever before.
Quantum entanglement is a strange phenomenon that sounds like science fiction to our classical-physics-focused minds. Basically, two or more particles can become so entwined that changing the state of one instantly changes that of its partners – no matter how far apart they are.
This mechanism – which Einstein himself dubbed “spooky” – can be tapped into to create quantum networks. Pairs of photons can be entangled and separated, allowing data to be “teleported” between them over long distances. As a bonus, these networks could be more secure, since any hackers would garble the data just by trying to read it.
Now, researchers at Fermilab, AT&T, Caltech, Harvard, NASA JPL and the University of Calgary have demonstrated sustained, very accurate quantum teleportation over long distances. The team sent information over 44 km (27 miles) with fidelity of over 90 percent – an accuracy record for this distance.
To do so, the team added a third “node” in the middle, between the sender and receiver. To get information from A to B, both parties first send a photon to C. The receiver, B, sends one member of an entangled pair and keeps the other. When A and B’s photons meet at C, they are then entangled, so that the information from A’s photon is transferred to both of B’s photons – the one it sent and the one it kept – thanks to the quantum entanglement link. In effect, it’s basically the same as teleporting information from A to B.
It’s not the longest distance quantum teleportation has been achieved. In 2015 information was teleported through optical fibers over 100 km (62 miles), and in 2017 Chinese scientists smashed the record by effectively teleporting data over 1,200 km (746 miles) using a satellite as the midpoint.
But the new experiments mark a breakthrough in fidelity over long distance. The 100-km record, for instance, managed about 80 percent accuracy, so 90 percent is an impressive improvement. The team also says that the experimental setup involved mostly off-the-shelf components, meaning a future quantum internet should be able to be built using existing infrastructure.
The research was published in the journal PRX Quantum.