Scientists are edging closer to creating a super-secure, super-fast quantum internet possible. They’ve now been ready to ‘teleport’ high fidelity quantum information over a complete distance of 44 kilometres (27 miles).
Both data fidelity & transfer distance are crucial, when it involves building a real, working quantum internet & making progress in either of these areas is cause for celebration for those building our next generation communications network.
In this case, the team achieved a greater than 90% fidelity (data accuracy) level with its quantum information, also sending it across extensive fibre optic networks almost like those that form the backbone of our existing internet.
“We’re thrilled by these results,” says physicist Panagiotis Spentzouris, from Fermilab high-energy physics & accelerator laboratory based at California Institute of Technology (Caltech).
“This is a key achievement on the way to building a technology which will redefine how we conduct global communication.”
Quantum internet technology uses qubits – unmeasured particles that remain suspended in a mix of possible states like spinning dice yet to settle.
Qubits are introduced to one another have their identities ‘entangled’ in ways which become obvious when they’re finally measured. Imagine these entangled qubits as a pair of dice while each can land on any number, they’re both guaranteed to add to 7 regardless of how far apart they’re. Data in one location instantly reflects data in another.
By clever arrangement of entangling 3 qubits, it’s possible to force the state of one particle to adopt the ‘dice roll’ of another by their mutually entangled partner. In quantum land, this is often nearly as good as turning one particle into another, teleporting its identity across a distance in a blink.
The entanglement still requires to be established in the beginning though and then maintained as the qubits are sent to their eventual destination via optical fibres (or satellites).
The unstable, delicate nature of quantum information makes-it tricky to beam entangled photons over long distances without interference, however, longer optical fibres simply mean more opportunity for noise to interfere with the entangled states.
In total, the lengths of fibre used-to channel each cubit added to 44 kilometres, setting a new limit to how far we send entangled-qubits and still successfully use them to teleport quantum information.
It’s never before been demonstrated to work-over such a long-distance with such accuracy and it brings a city-sized quantum network closer to reality, even though, there are still years of work ahead to make that possible.
“With this demonstration, we’re beginning to lay the foundation for the construction of a Chicago area metropolitan quantum network,” says Spentzouris.
Quantum entanglement & data teleportation is a complex science and not even the experts fully understand how it’d ultimately be utilized in a quantum network. Each proof of concept like this that we get puts us a little-closer to making such a network happen though.
As well as promising huge boosts in speed & computational power, a quantum internet would be ultra-secure, any hacking attempt would be nearly as good as destroying the lock being picked. For now atleast, scientists think quantum internet networks will act as specialist extensions to the classical internet, instead of an entire replacement.
Researchers are tackling quantum internet problems from all different angles, which is why you will see a number of distances mentioned in studies, they are not all measuring the same technology using the same equipment, to check the same standards.
What makes this study special is the accuracy and distance of the quantum entanglement teleportation, also as the ‘off the shelf’ equipment used, it should theoretically be relatively easy to scale-up this technology using the hardware, we’re already got in place.
“We are very proud to have achieved this milestone on sustainable, high-performing & scalable quantum teleportation systems,” says physicist Maria Spiropulu from Caltech.
“The results will be further improved with the system upgrades we’re expecting to complete by the second quarter of 2021.”
The research has been published in PRX Quantum.