Richard Feyman once remarked “if you think you understand quantum mechanics, then you don’t understand quantum mechanics” and virtually every cutting edge experiment in the field seems to prove him right. Well, to be fair, physicists understand quite a bit about quantum mechanics but there are still quite a few mysteries to clarify including that of quantum entanglement. Usually, when you entangle two particles like photons they can be described by the same wave functions even if there are huge distances between them. But how? Do they just instantly mirror each other or is there some sort of delay in when the phenomenon spreads between the entangled photons? That’s what physicists in Switzerland tried to find out with pretty amazing results and as it turns out, while most phenomena in the universe fall in line with the rules of relativity, the quantum world acts as if it’s only begrudgingly obeying them, barely avoiding violating them through technicalities.
After a stream of entangled photons was fired through a fiber optic cables which split them to hit detectors 11 miles apart, the photons were still showing all the signs of entanglement after hitting their detectors. For that to happen, the quantum phenomenon must have been traveling faster than the speed of light. In fact, the math suggests an astonishing 10,000 times the speed of light if not outright instantaneously. But hold on a second, doesn’t that violate special relativity which dictates that nothing can move faster than the speed of light except the fabric of space itself? Well, the catch is that you shouldn’t be able to transmit any sort of information with a quantum phenomenon because you’re only learning about the photon’s states after they hit the detectors, and photons can only travel at the speed of light so the speed of light limit is technically not being violated. So even though we can induce macro objects to exhibit quantum phenomena, there’s a limit to when we can actually collect any information about what’s happening to them.
See: Salart, D., et al. (2008). Testing the speed of ‘spooky action at a distance’ Nature, 454 (7206), 861-864 DOI: 10.1038/nature07121
[ photo illustration by Derek Prospero ]