Scientists have successfully teleported the quantum state of a photon to acrystal over 25 kilometres of optical fibre, showing that information can be teleported from light into matter.
The breakthrough was made by a team at the University of Geneva, and according to their press release, the results prove “that the quantum state of a photon can be maintained whilst transporting it into a crystal without the two coming directly into contact“.
Quantum teleportation involves moving tiny bits of data from one place to another instantly, through a phenomenon know as quantum entanglement. Entanglement is when two linked particles act like twins, even when they’re separated, and means that information can instantly be passed from one to the other without them touching.
Researchers are fascinated by quantum teleportation because it could revolutionise the way we carry and transmit data. But they’ve struggled until now to find ways in which quantum information stored in light can be used in existing communication systems, which are matter-based, and transferred further than a few kilometres.
In this new experiment, the physicists took two entangled photons and sent one along 25 kilometres of optical fibre, while the other was sent to a crystal, which stored its information.
A third photon was then sent like a billiard ball into the optical fibre to hit the first photon, obliterating them both.
But the scientists discovered that the information from that third photon wasn’t actually destroyed, but had in fact been transferred into the crystal containing the second entangled photon. Their results are published in Nature Photonics.
This shows “the quantum state of the two entangled photons which are like two Siamese twins, is a channel that empowers the teleportation from light into matter,” co-lead researcher Félix Bussieres said in the press release.
“One needs to imagine the crystal as a memory bank for storing the photon’s information; the latter is transferred over these distances using the teleportation effect,” the press release explains.
There is still a long way to go before we’re using quantum teleportation in communication systems, but this is an important step that suggests the “vehicle” of the information doesn’t matter so much. As the authors write in Nature Photonics, the experiment demonstrates “quantum teleportation of the polarisation state of a telecom-wavelength photon onto the state of a solid-state quantum memory.”
And that opens up a lot of possibilities for future quantum teleportation research.