At the heart of the history of quantum entanglement lies a famous debate between two groups of physicists, a clever paradox and an iconoclastic way out of it.
God does not play dice with the universe. He plays an ineffable game of his own devising, which might be compared, from the perspective of any of the other players, to being involved in an obscure and complex version of poker in a pitch dark room, with blank cards, for infinite stakes, with a dealer who won’t tell you the rules, and who smiles all the time.
– Terry Pratchett
In June 2017, a group of scientists in China announced that they had used the country’s Micius satellite, launched a year earlier, to teleport information from Earth to space in an instant. In other words, they had moved it across over 500 km in literally no time. To achieve this, they had relied on a natural phenomenon called quantum entanglement. The name itself correctly suggests that it belongs in the realm of quantum mechanics, the realm of subatomic particles. The Chinese scientists’ experiment had bested a previous record, when in 2012 their leader himself had lead a team that had teleported information across 97 km.
Very few ideas in science enjoy the popularity that teleportation does: it has been equally awe-inspiring among scientists and laypeople. To the more inspired, what is fascinating is not how an object “leaves” one point in space and “arrives” at another but that it traverses the intervening distance in an instant. The implications of such travel are significant at first sight. The day when we will be able to “beam” a person up and down across space – a la Star Trek – might still be very far away but in the meantime we could use quantum entanglement to, for example, teleport digital security keys between two computers and prevent most forms of eavesdropping by hackers.