Scientists take leap toward 'quantum internet'

Researchers have sent data across three physical locations using a technique dubbed 'qubit teleportation.'

Researchers from Delft University of Technology in the Netherlands have teleported quantum information between two network nodes that were not directly linked to each other - a major step forward in enabling a future quantum internet.

The new technique will enable information to be transported in an instant, they say, paving the way for a quantum computing revolution as well as a major shift in network architecture.

Quantum computers work in a fundamentally different way to classic computers, using qubits (quantum bits) as the basic building blocks of computing. Unlike regular binary digits (bits) that store information as either a 0 or 1, qubits can store a combination of both through superposition.

For a quantum computer to work properly, qubits have to remain 'entangled' with each other, meaning that the state of one qubit instantaneously affects the state of another, even when they are physically separate.

In a study published in science journal Nature, the researchers describe how they accomplished a breakthrough in qubit teleportation across non-adjacent nodes - or to put it another way, over a network.

The scientists used a nitrogen vacancy system, which is essentially a tiny empty space inside a synthetic diamond that can be used to trap electrons.

The team created three such systems, which they dubbed Alice, Bob, and Charlie, and then entangled these systems by sending individual photons between them.

The researchers first entangled two electrons, one belonging to Alice and the other to Bob. Both electrons had the same spin and were therefore entangled in the same quantum state, with each holding the same information.

This quantum state was then transferred to another qubit, a carbon nucleus, inside Bob's synthetic diamond.

By doing so, researchers were able to entangle Bob's electron with another electron belonging to Charlie.

By performing a specific quantum operation on both of Bob's qubits — the electron and the carbon nucleus — the researchers were able to glue the two entanglements together: Alice plus Bob glued to Bob plus Charlie.

Due to the fact that Alice and Charlie were indirectly entangled with one another, the researchers were able to transported data from Alice to Charlie.

"It's really teleportation as in science-fiction movies," said Ronald Hanson, the Delft physicist who supervises the team.

"The state, or information, really disappears on one side and appears on the other side, and because it's not travelling the space in between, [the data] can also not get lost."

Even though the teleportation occurred at a distance of only 60 feet, the researchers are optimistic that this can be achieved over a distance of several miles.

In the long run, it could help create a new network of quantum computers or a quantum internet that is exceptionally safe, trustworthy, and secure.

"We are now building small quantum networks in the lab," said Hanson. "But the idea is to eventually build a quantum internet."

Researchers think that quantum computers can potentially speed up the discovery of new medications, improvements in artificial intelligence, and even be used to create encryption methods that are even more secure.

The detailed findings of the study are published in Nature.