Teleportation breakthrough paves the way for quantum internet

A Dutch team has succeeded in exchanging qubits between distant nodes with no direct connection between sender and receiver.

Quantum computing is advancing in both tiny and giant steps. Tiny, because what is achieved involves unique breakthroughs of limitations; giant, because each stride opens up a world of infinite possibilities.

One such step has been taken by a research team led by Ronald Hanson, a physicist at the QuTech laboratory at Delft University in the Netherlands, which has succeeded in teleporting quantum information via a rudimentary network with no direct connection between sender and receiver.

This quantum leap, published Wednesday in Nature, means we are one step closer to a quantum internet which would then lead to an entirely new kind of computer that could carry out tasks that would take supercomputers thousands of years in a matter of minutes, paving the way for huge progress in the realms of medicine and artificial intelligence.

Basic teleportation had already been achieved – Hanson’s team and others have already demonstrated it – but only between two points, or adjacent nodes, named Alice and Bob. Now, Hanson’s team have managed to link this pair at a distance with a third, Charlie. The trio form the first network that, although rudimentary, allows us to contemplate a quantum internet, with infinite possibilities for computation and for observing a hitherto unknown world.

Explaining the relevance of this primordial quantum network, Hanson says: “Regarding quantum communication, our work shows how teleportation can be used in a real network environment, with nodes that have no direct connection. In a future quantum internet, such teleportation will be the main way to transfer quantum information over large distances. Our network can be viewed as a modular quantum computer [where the nodes are the modules]; our work shows that nodes can exchange quantum information, even if they are not on a single chip.”

To understand the progress made by Hanson’s team, we must look back at the previous achievements in this field. The first of these was the demonstration that teleportation is possible in the quantum world. The late Israeli physicist, Asher Peres, who died in 2005, anticipated the phenomenon in the Physical Review Letters in 1993. When a reporter asked him if quantum teleportation could transport the soul as well as the body, the physicist replied: “Not the body, just the soul.”

This anecdote is significant for understanding quantum teleportation, where it is not matter that is transported through a medium but the information that confers its properties. As Hanson explains: “The key feature of quantum teleportation is that the quantum information itself is actually teleported: it does not travel through space or fiber. The entangled pair of qubits, which is the resource for executing the teleportation – the ‘teleporter’ – is prepared by using a signal through fiber.” Another term for this phenomenon was coined by Albert Einstein: “Spooky action at a distance.” He himself deemed it impossible.

The Source: english.elpais.com