Motherboard

Spooky action at a 10 mile distance.

Imagine communication without medium or time constraints. That is: instant transfer of information over unlimited distances with no need for a communication channel of any sort (like, no wires or radio waves). On one hand, that’s a sugar-coated oversimplification of what quantum teleportation-slash-entanglement might mean but, on the other hand, yeah, that’s what we’re looking at. And a recent paper in Nature (via Ars Technica) announced that Chinese researchers have accomplished quantum teleportation over a distance of ten miles in a “free-space” public environment.

Let’s rewind just a second. Quantum entanglement is what Einstein famously called “spooky action at a distance”—because it appears to violate the laws of relativity, e.g. involve moving fast than light.

Entanglement means that two particles that originate in a shared quantum state and are then separated over an infinite time/distance stay entangled. What that means is that if we somehow influence the quantum state of one particle, the quantum state of the other particle changes to match. Nothing is “transferring” over the time/distance—except the initial separation of the particles—rather the particles just are still existing in the same state, just not next to each other. Ow, right?

Entanglement is something that’s been done many times in the sort of limited experiments designed to show just that it can be done, but this is more along the lines of it can be done, and used. Previously, the second photon (the particle) had to be separated from the first via “noisy” fiber lines to ensure that it stayed in the same state, stayed entangled, with the first. Sending it via free-space as researchers have done here means that the second photon was send via the open air in a Chinese city, while staying entangled (or “in communication”) with the first.

It’s difficult to image a time when this stuff won’t be mind-bending just in principle—but now it appears to be getting close to practical, too.