Researchers at the University of Geneva, led by Professor Nicolas Gisin, have successfully teleported the quantum state of a photon – in other words, all the information on one particle of light – through an optical fiber connection to a crystal 25 kilometers away. This experiment amply surpassed the record achieved by the same research group in 2003 and detained ever since, involving a distance of 6 kilometers.
This experiment may well remind us of all those films where people are tele-transported instantly through space, but actually we’re still very far away from the possibility of transferring even the smallest object… Nevertheless, we have just taken a momentous step beyond the limits of what was previously believed to be possible.
Obviously, it’s no simple task to understand the finer scientific points of such a feat, but one can start by imagining two entangled photons – that is, two photons inextricably linked at the most infinitesimal level by their joint states. One is propelled along an optical fiber (the 25 kilometers mentioned earlier), but not the other, which is sent instead to a crystal. It then becomes a bit like a game of billiards, with a third photon hitting the first and thus obliterating both of them. Scientists measure this collision. But the information contained in the third photon is not destroyed… on the contrary it finds its way to the crystal, which also contains the second entangled photon.
FÃ©lix BussiÃ¨res, the main author of this publication, explains that one observes "that the quantum state of the two elements of light, these two entangled photons which are like two Siamese twins, is a channel that empowers the teleportation from light into matter".
From there, it is a small step to conclude that, in quantum physics, the state takes precedence over the 'vehicle' - in other words an item's quantum properties transcend its classical physical properties. A step that, in the light of this research, maybe one can now consider taking.
Passing from light into matter, using teleportation of a photon to a crystal, shows that, in quantum physics, it is not the composition of a particle which is important, but rather its state, since this can apparently exist and persist regardless of such extreme differences as those which distinguish light from matter.
This study is part of a line of research which is of fundamental importance in the context of developing the first quantum computers, which will feature greatly superior computing power and speed compared to today’s computers.