Quantum teleportation has just been carried out with an accuracy of 90% over a distance of 44 km

Scientists are on the cusp of making an ultra-secure, ultra-fast quantum internet possible: they have now been able to “ teleport ” high-fidelity quantum information a total distance of 44 kilometers (27 miles).

Data fidelity and transfer distance are essential when it comes to building a truly functioning quantum internet, and making progress in either of these areas is cause for celebration for those building our. new generation communication network.

In this case, the team achieved a level of fidelity (data accuracy) of over 90% with their quantum information, and sent them over vast fiber optic networks similar to those that form the backbone of our internet. existing.

“We are delighted with these results,” says physicist Panagiotis Spentzouris, of the Fermilab Accelerator and Particle Physics Laboratory based at the California Institute of Technology (Caltech).

“This is a key achievement on the way to building a technology that will redefine the way we conduct global communication.”

Quantum Internet technology uses qubits; unmeasured particles that remain in suspension in a mixture of possible states like spinning dice yet to settle.

The Qubits that are presented to each other have their identities “entangled” in such a way that they become evident once they are finally measured. Imagine these tangled qubits as a pair of dice – while each can land on any number, they’re both guaranteed to add up to seven no matter how far apart. Data from one location instantly mirrors data from another.

By an intelligent arrangement of three entangled qubits, it is possible to force the state of one particle to adopt the “dice roll” of another via their mutually entangled partner. In quantum earth, it’s as good as transforming one particle into another, teleporting its identity from a distance in the blink of an eye.

However, entanglement still needs to be established in the beginning and then maintained as the qubits are sent to their final destination via fiber optics (or satellites).

However, the unstable and delicate nature of quantum information makes it difficult to beam entangled photons over long distances without interference. Longer optical fibers simply mean more opportunities for noise to interfere with entangled states.

In total, the lengths of fiber used to channel each cubit have added up to 44 kilometers, setting a new limit on how far we can send entangled qubits while successfully using them to teleport quantum information.

It has never been shown before to operate over such a long distance with such precision, and it brings a city-sized quantum network closer to reality – even if there are still years of work to be done. do to make this possible.

“With this demonstration, we begin to lay the groundwork for building a metropolitan quantum network in the Chicago area,” says Spentzouris.

Quantum entanglement and data teleportation is a complex science, and even experts don’t fully understand how it could ultimately be used in a quantum network. Every proof of concept like this that we get gets us one step closer to making such a network.

Besides promising huge gains in speed and computing power, a quantum internet would be ultra-secure – any hacking attempt would be as good as destroying the selected lock. For now at least, scientists believe that quantum Internet networks will act as specialized extensions of the classical Internet, rather than a complete replacement.

Researchers are tackling the problems of the quantum internet from all angles, which is why you’ll see a variety of distances mentioned in the studies – they don’t 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 entanglement teleportation, as well as the “ standard ” equipment used – theoretically it should be relatively easy to extend this technology using material that we already have in place. .

“We are very proud to have reached this milestone in sustainable, high performance and scalable quantum teleportation systems,” said physicist Maria Spiropulu of Caltech.

“The results will be further improved with the system upgrades that we plan to complete by the second quarter of 2021.”

The research was published in PRX Quantum.

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