Awesome

"measurements taken at different points in space and time appear to affect each other, even though there is no mechanism that allows information to travel between them."

I kinda like the time can be symmetric like this. It says something about the Universe, i'm just not clear o. What exactly that is; apart from Awesome.

Wow!

Quantum is already changing our lives but it is going to drastically change the human way of life in the future. There's no telling what crazy shit they'll be able to pull off

I think the point is, in the future it may change the past o_O

I KNEW we should have been sending halves of entangled photon pairs into the future all these years! Now we will NEVER know what stocks to buy.

Ok, so whatever mechanism you use to explain the 'spooky action at a distance' effect. Now you must extend it to treat space-time distances as unimportant rather than just spatial ones.

I guess it is not too surprising; if messages could go faster than the speed of light, then timetravel would be possible; so within the context of this faster than light 'interaction' it is no surprising that backward time interaction can occur.

However just as it can't be used to transmit information faster than light, it also can't transmit info into the past - thus in some sense i don't think it violates causality.

Yeah right, orathaic. You know that it's only another five years till we figure out time travel, go back to try to stop WWII, fail again, and start this whole cycle over again. I mean, this is already, what -- the fifth time? And I still can't beat freaking Dejan.

Umm, are these actual experiments or theoretical physics? - aka Pie in the Sky!

lol.

They're actual experiments. Also, they matched theory, showing that, in fact, it was not pie in the sky.

"The picture certainly looks like future events influence the past, a view any right-minded physicist would reject. "

I'm still calling PIE IN THE SKY.

word.

Pie in the sky experimental data? Ummm sure....

But as i think i've claimed (though my understanding is limited) no causal violations...

Even though, by the description of the experiment, i can't figure out how...

Causality is probably the wrong way to think about what's going on. You get counterintuitive answers when you try and describe many quantum processes that way, and in terms of relativity, what the experiment is saying is the same as previous results.

When A and B happen at different points (a and b) in space and time, there are three possibilities:

1) After A, light could travel from a to b before B: In that case, A happens before B to all observers. A can affect B.

2) After B, light could travel from b to a before A: in that case, B happens before A to all observers. B can affect A.

3) Neither is true. In that case, different observers might disagree on which one happened first; neither one can affect the other. However, all observers will be able to calculate that some observers will have a different view of the situation than they do.

However, quantum entanglement allows "action at a distance", which is a way of letting A and B affect each other in category 3. We do not currently understand why this is true; models incorporate it, experiments verify it, and it works mathematically, but we have no good intuition for why this should be true.

Previous experiments testing entanglement used a situation in which, to an observer in the laboratory, A appeared to happen before B, yet with a small enough separation that it fell into category 3), not category 1). As a result, in previous experiments, an observer traveling at the right velocity would have seen B appear to happen before A. So, we would expect the result should be the same if B were, to the laboratory observer, slightly before instead of after A, yet still in category 3). And, that experiment has now been done, and this turns out to be the case.

'However, quantum entanglement allows "action at a distance", which is a way of letting A and B affect each other in category 3. We do not currently understand why this is true; models incorporate it, experiments verify it, and it works mathematically, but we have no good intuition for why this should be true.'

Does this exclude A from being affected by B in case 1) or B being affected by A in case 2) ?

My understanding is that it doesn't matter whether light can travel between the two the quantum action at a distance just allows a 'kind' of interaction (which isn't a kind described by the kinds of classical interactions which we intuitively understand, and require for causality)