Scientists teleport quantum information across four-mile cable

A pair of research teams -- one in Canada and one in China -- just showcased quantum teleportation across four-mile cables. The feat promises to pave the way for a quantum internet.

Quantum teleportation relies on a phenomenon known as quantum entanglement, which describes two inextricably linked particles, whereby the measure or manipulation of one particle is observed in the other, regardless of time or location.

A change in a light particle's state can be transferred, or teleported, to its partner particle without any physical contact or information passing between them.

Researchers recently demonstrated the phenomenon in previously laid optical fiber networks.

If scientists are going to take quantum physics out of the laboratory and into the real world of telecommunications, taking advantage of existing infrastructure is vital.

Before an information highway is built based on quantum teleportation, it's likely the technology will first be incorporated into information security. In the recent demonstrations, scientists showcased the technology's potential for information encryption.

In the two experiments, researchers used three particles. One particle was sent classically across a fiber-optic cable from point A to point B. Then, a pair of entangled particles were released. One stayed behind at point A, while the other was sent to point C.

The difference between the particles at B and C is measured, revealing the change in the quantum state of point A.

The same feat was performed in both Calgary and the Chinese city of Hefei, though each experiment involved a slightly different setup. Both experiments were detailed in the journal Nature Photonics.

Scientists have previously demonstrated quantum teleportation across longer distances, though using lasers. The latest experiments offer proof that existing fiber-optic networks can be used for quantum communications.

Though quantum communication may not make the information highway any faster, it could make it much more secure, as quantum communication is virtually unhackable.