They say the results are clear but do not measure the speed of spooky action directly. Instead, the results place a lower bound on how fast it must be. The answer is that it is at least four orders of magnitude faster than light, and may still turn out to be instantaneous, as quantum mechanics predicts.

via Chinese Physicists Measure Speed of “Spooky Action At a Distance” | MIT Technology Review.

I really hope we see more work on quantum entanglement and non-locality, the source of “Spooky action at a distance.” Quantum entanglement is a non-intuitive phenomena in which the quantum states of two or more objects becomes linked in such a way that a change in on state affects the other states. If entanglement acts non-locally, and to date the evidence is that it does, the changes to entangled states propagates (nearly) instantaneously, no matter how far apart the objects may be, without anything in between to mediate the interaction. I believe this is suggestive of our Universe existing inside a simulation.

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*Posted by Fred on March 11, 2013*

https://ninthlaw.wordpress.com/2013/03/11/physicists-measure-speed-of-spooky-action-at-a-distance-mit-technology-review/

## Amaurea

/ March 15, 2013Isn’t this phenomenon much less spooky in non-Copenhagen interpretations of quantum mechanics? In the many worlds interpretation no non-local interactions are involved at all.

## Fred

/ March 16, 2013Good question. I’ll need to think about it, but at first take, I’m not sure it is true that in a Many-Worlds interpretation there are only local interactions. If it were true, then we have (probably) have a proof that MW is false in our universe, because if Bell’s Inequality holds, it means the universe can’t be local. There is no final definitive test of Bell’s Inequality yet, but to date the results of several experiments have agreed quite well with the “no local realism” view.

The problem is synchronizing the results of distant measurements, and that is a temporal issue which is present even in a Many-Worlds interpretation. I think.

## Fred

/ March 16, 2013MWI can be a local theory, but it requires abandoning counterfactual definiteness (being able to speak meaningfully about measurements you didn’t make). Something has to limit the possible worlds so that entangled systems which display correlation are only brought into existence with the correlation baked in, so to speak. At least, that’s the idea I’m getting after thinking about this for a bit. I’m not (yet) clear on if we can choose between locality and counterfactual definiteness for our MWI theories. So many thoughts, so little time.

Thanks! That was an excellent observation. I’m going to spend a little more time thinking about it.