Long-range, high-fidelity teleportation paves the way for the quantum internet


A quantum internet would be much faster and more secure than the one you are using right now – and now such a network may be one step closer to reality. Scientists have used quantum teleportation to send information over long distances, with higher fidelity than ever before.

Quantum entanglement is a strange phenomenon that looks like science fiction to our minds focused on classical physics. Basically, two or more particles can become so intertwined that changing the state of one instantly changes that of its partners, regardless of their distance.

This mechanism – which Einstein himself called “frightening” – can be harnessed to create quantum networks. Pairs of photons can be entangled and separated, allowing data to be “teleported” together over long distances. As a bonus, these networks could be more secure, as any hacker would scramble the data just by trying to read it.

Today, researchers at Fermilab, AT&T, Caltech, Harvard, NASA JPL, and the University of Calgary have demonstrated sustained and highly accurate quantum teleportation over long distances. The team sent information for 44 km (27 miles) with a fidelity of over 90 percent – an accuracy record for that distance.

To do this, the team added a third “node” in the middle, between the sender and the 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 the photons of A and B meet in C, they are then entangled, so that the information of the photon of A is transferred to the two photons of B – the one it sent and the one it kept – thanks to the quantum entanglement link. Indeed, it is basically the same as teleporting information from A to B.

This is not the longest quantum teleportation distance that has been achieved. In 2015, information was teleported via optical fibers for 100 km (62 miles), and in 2017, Chinese scientists broke the record by effectively teleporting data over 1,200 km (746 miles) using a satellite as a point. median.

But the new experiences mark a breakthrough in long-distance loyalty. The 100 km record, for example, achieved an accuracy of around 80 percent, so 90 percent is an impressive improvement. The team also says the experimental setup mostly involved off-the-shelf components, meaning that a future quantum internet should be able to be built using existing infrastructure.

The research was published in the journal Quantum PRX.

Source: Fermi Laboratory, Caltech

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