One of the notable science stories of 2017 concerns a strange phenomenon that falls out of the equations of quantum physics, whereby measuring the property of a subatomic particle here, causes an instantaneous change in a twinned particle existing over there – with the rub being that ‘over there’ might be a thousand miles away!
This appears to defy Einstein’s iron-clad principle that ‘nothing travels faster than light’ because it is instantaneous. That’s right: it doesn’t make any difference how far away the twinned particle is, the change there happens the instant the measurement is taken here. This bothered Einstein – hence his dismissive description of it as ‘spooky action at a distance’. It was one of several consequences of quantum physics that Einstein just couldn’t accept, and indeed he devoted considerably ingenuity in his later years to showing how it couldn’t be the case. But at the time of his death, it was still an open question.
However, it has since been confirmed by experimental observation that the ‘spooky action’ does indeed take happen, exactly as quantum physics predicted. This was the result of the work of some brilliant physics, first by John Stewart Bell, who worked out what it would take to confirm it, and then by Alain Aspect, who actually carried out the experiments. Quite how it happens is still an unsolved mystery, but there is no doubt that it does.
So now to the story. Using the Chinese satellite Micius, launched in August 2016, Jian-Wei Pan, a physicist at the University of Science and Technology of China in Shanghai, got the chance to test the idea on a large scale. The satellite is the foundation of the $100 million Quantum Experiments at Space Scale program. In their first experiment, the team sent a laser beam into a light-altering crystal on the satellite. The crystal emitted pairs of photons entangled so that their polarization states would be opposite when one was measured. The pairs were split, with photons sent to separate receiving stations in Delingha and Lijiang, 1200 kilometers apart, in the mountains of Tibet, reducing the amount of air the fragile photons had to traverse.
Recently in Science, the team reported simultaneously measuring more than 1000 photon pairs. They found the photons had opposite polarizations far more often than would be expected by chance, thus confirming spooky action over a record distance 1.
Apart from being an amazing piece of technological innovation, what’s impressive about this result is the distance involved; until now, such experiments had been limited to much smaller scales, but this achievement opens up the possibility of commercial applications in satellite communications. And what it gives you, is the ability to make absolutely bullet-proof encryption – security which no amount of hacking will ever penetrate, because as soon as anyone reads one of the paired keys, the other one ‘knows’ it. (Let’s not dwell on how annoying it is, the lengths you have to go to, just to ward off hackers…)
Enter the Hippies
Anyway, aside from the intrinsically interesting nature of this achievement, there’s another interesting back-story in play. And that is the origin of the idea of using ‘spooky action at a distance’ for encrypted communications at all. This was the brain-child of a bunch of brilliant wunderkinden – mainly un- or under-employed physicists – who met in San Francisco on the 1970’s and formed The Fundamental Fysiks Group. Members included Jack Sarfatti, Saul-Paul Sirag, Nick Herbert and Fred Alan Wolf (clockwise, at left, circa 1975). They were very counter-cultural in orientation, quite at home in the outer reaches of speculative physics (among other places!) – and their exploits and ideas are explored in the fascinating 2012 book, How the Hippies Saved Physics, by David Kaiser.
“What happens when you mix the foundations of quantum mechanics with hot tubs, ESP, saffron robes, and psychedelic drugs? How the Hippies Saved Physics chronicles the wild years of the 1970s when a group of largely unemployed physicists teamed up with LSD advocate Timothy Leary, EST founder Werner Erhard, telekinesist Uri Geller, and a host of other countercultural figures to mount a full-scale assault on physics orthodoxy. David Kaiser’s masterly ability to explain the most subtle and counterintuitive quantum effects, together with his ability to spin a ripping good yarn, make him the perfect guide to this far-off and far-out era of scientific wackiness.” ~ Seth Lloyd, author of Programming the Universe
And so, here we are, 40-odd years later, and physicists are turning these ideas into reality. ‘Spooky action at a distance’, indeed!