Reacción a "Reactions to experimental achievement that would be "a step towards the quantum internet""

This work is an experimental achievement that seeks to open the door to a large number of possibilities, with the quantum internet as the ultimate goal.

Quantum teleportation has been experimentally tested in multiple occasions and circumstances since it was theoretically formulated in 1993 by a group of six theoretical physicists. It evokes forms of transport from science fiction, but more pragmatically it is the basic operation for quantum communications.

It allows quantum information to be transported between a sender (Alice) and a receiver (Benedict) separated by a certain distance and without violating any of the fundamental laws of physics, such as Einstein's relativity or Heisenberg's indeterminacy principle. But for the transport of quantum information to make more versatile quantum communications possible, we need more nodes (Alice, Benedict, Charles, etc.) and at arbitrarily large distances.

In the experiment reported in Nature by Sophie Hermans, Ronald Hanson and co-workers, a teleportation between Alice's node and Benedict's node is achieved with an extra node of Charles acting as an intermediary. They use spin cubits (quantum information units) embedded in diamonds and connected by fibre optic links. Teleporting states is achieved by guaranteeing their quantum character and with high efficiency. The team has introduced many technical improvements that they hope will be reusable in other quantum platforms, but more information on the range of distances between nodes is lacking.

The use of intermediary nodes in teleportation will make it possible to transport the quantum entanglement over long distances and prevent it from deteriorating along the way. This is the basis for so-called quantum repeaters, the quantum version of the electromagnetic signal repeaters that make radio, television and more modern mobile communications possible.

Quantum teleportation will in the future allow quantum communications to be unified with quantum computing, taking the form of a quantum internet: the nodes will be quantum computers communicating with each other via quantum links using teleportation.

All in all, the current experiment is a necessary advance, but not yet sufficient to cover all the possibilities that will open up when we can further master quantum teleportation in a practical and routine way, and in particular, when we can teleport over sufficiently large distances.