Scientists are approaching the possibility of a super-secure and very fast quantum internet: they have now been able to “teleport” high-fidelity quantum information over a total distance of 44 kilometers (27 miles).
Both data fidelity and transfer distance are crucial when it comes to building a real and functional quantum internet, and progress in any of these areas is a celebration for those who build our next-generation communications network.
In this case, the team obtained a level of fidelity (data accuracy) higher than 90% with its quantum information, as well as sending them through extensive fiber optic networks similar to those that form the backbone of our existing Internet.
“We are delighted with these results,” says physicist Panagiotis Spentzouris, of the Fermilab particle physics and acceleration laboratory based at the California Institute of Technology (Caltech).
“This is a key achievement in building a technology that redefines the way we conduct global communication.”
Quantum technology on the Internet uses qubits; unmeasured particles that remain suspended in a mixture of possible states, such as spinning dice, have not yet been established.
Qubits that present themselves to each other have their identities “tangled” in ways that become apparent once they are finally measured. Imagine these tangled qubits as a pair of dice – while each can land on any number, both are guaranteed to add up to seven, no matter how far away they are. Data in one location instantly reflects data in another location.
By the clever arrangement of tangling three qubits, it is possible to force the state of one particle to adopt the “rolling of the dice” of another through their mutually tangled partner. In the quantum country, this is as good as transforming one particle into another, teleporting its identity over a distance in an instant.
The confusion has yet to be established at first, and then maintained as the qubits are sent to their final destination by fiber optics (or satellites).
However, the unstable and delicate nature of quantum information makes it difficult to transmit tangled photons over long distances without interference. Longer fiber optics simply mean more opportunities for noise to interfere with tangled states.
In total, the fiber lengths used to channel each elbow have been added to 44 kilometers, setting a new limit on how far we can send tangled qubits and can still use them successfully to teleport quantum information.
It has not been proven so far that it works such a long distance with such precision and brings a quantum network of urban dimensions closer to reality – even if there are many years of work to make this possible.
“With this demonstration, we are beginning to lay the groundwork for building a metropolitan quantum network in the Chicago area,” says Spentzouris.
Quantum involvement and teleportation of data is a complex science and not even experts fully understand how it could eventually be used in a quantum network. Every proof of this concept we get puts us a little closer to creating such a network.
In addition to promising huge increases in speed and computing power, a quantum internet would be ultra-secure – any attempt at hacking would be as good as destroying the chosen block. At least for now, scientists believe that quantum internet networks will act as specialized extensions to the classic internet, rather than as a complete replacement.
Researchers approach quantum internet problems from all different angles, which is why you’ll see a variety of distances mentioned in the studies – not all measure the same technology, using the same equipment, to test the same standards.
What makes this study special is the accuracy and distance of the quantum tangle teleportation, as well as the equipment used on the shelf – theoretically it should be relatively easy to extend this technology using the hardware we have already developed. .
“We are very proud to have achieved this stage in sustainable, high-performance and scalable quantum teleportation systems,” says physicist Maria Spiropulu of Caltech.
“The results will be further improved with the system updates we expect to complete by the second quarter of 2021.”
The research was published in Like PRX.