Scientists from Delft teleport information: “Switch to indecipherable communication”

Researchers from QuTech, a collaboration between TU Delft and TNO, have a scoop teleporting quantum information between two nodes that were not directly connected to each other. According to QuTech, in the long term, this teleportation could constitute the “backbone” of an ultra-secure quantum Internet.

“We’ve shown that we can pull it all together, to make it all work at the same time. Because you’re dealing with things that have conflicting interests, so to speak. It’s a blueprint of what becomes possible,” says Hans Beukers, one of the scientists who collaborated on the research†

qubits

Quantum computers calculate with quantum physics, the theory of the world at the smallest scale. Unlike ordinary computer bits, quantum bits (qubits) can be not only 0 or 1, but also 0 and 1 at the same time. As a result, quantum computers can perform calculations that are not possible with current supercomputers. Quantum computers can therefore contribute to all kinds of important research, such as new materials that could cause an energy revolution or medicines adapted to the individual.

Connecting quantum computers requires a different kind of internet, which uses “tangle” between qubits. What you do with one qubit immediately affects the other, even if those qubits are very far apart.

The Delft researchers “entangled” three qubits to create a quantum network. Until now, this was only possible between two points.

From Alice to Charlie

Alice, Bob and Charlie are what researchers call the three knots. They used the entanglement to teleport information from Alice to Charlie, skipping the middleman Bob.

Alice and Bob were connected by fiber, Bob and Charlie, but Alice and Charlie had no physical connection. Bob enabled the teleportation of information between Alice and Charlie by reconciling two entanglements.

When measuring quantum states, information is immediately lost. This also happens with a measurement to Charlie, but then this information immediately appears on Alice’s side. The qubit is transferred encrypted, with Charlie’s measurement result determining the key. Alice then performs the quantum operation necessary to decipher the qubit.

don’t crack

One of the great promises of a quantum internet is communication that cannot be intercepted or exploited. If someone tried this, the information would disappear instantly. Only the sender and recipient can access certain information.

“With today’s computers and the Internet, anything can be hacked as long as you have a powerful enough computer. Mathematical security can be broken, physics can’t. It’s inherently safe, it’s unbreakable,” says Beukers. “With the quantum internet, you immediately notice if someone is manipulating certain information.”

He gives the example of a government agency sending nuclear secrets to another government organization. “It may not be possible to decipher a message like this now, but you want it to still be 30 years from now. That’s the promise of the quantum internet.”

In addition to secure communication, the quantum internet could also offer more privacy, says Beukers. “The services then no longer need all kinds of information about you in order to be able to recognize you and help you.”

Increase

There is still a lot of work to do before quantum computers work together in an international network. “We need to get the technology out of the lab first and make it more robust in the field.” According to the researchers, this was almost the maximum achievable with the design used. “To make it scalable, a different setup is needed. We’re looking for other particles to create tangles with. Experiments are underway, but they’re still in their infancy.”

Research is also being conducted on the use of infrared light to make the quantum internet possible via normal fiber optic cables. “It will probably take ten years before there is a global network of quantum computers.”