Not to diminish the scientific value of this discovery, but there's also another way to send messages to the future: <a href="http://en.wikipedia.org/wiki/Writing" rel="nofollow">http://en.wikipedia.org/wiki/Writing</a>
Forgive my ignorance of quantum physics, but would it be possible to use entanglement to send messages back in time? If not, why would entanglement work in only one direction (forwards)?<p>There is a causality argument, but I don't why it would be impossible that reading a message from the future cannot alter that future. Just because a future universe occurred once doesn't mean that it has to occur again once particles have been entangled, does it? Aside from being very strange, would such a scenario violate any known laws of physics?<p>There is this: <a href="http://en.wikipedia.org/wiki/No-communication_theorem" rel="nofollow">http://en.wikipedia.org/wiki/No-communication_theorem</a>, which, unfortunately, is beyond me.
There are prosaic (by which I mean classical, non-quantum) means of accomplishing the same thing, e.g. encrypt a classical message using a one-time pad and send the resulting ciphertext and keystreams in opposite directions at the speed of light. The original data can be recovered if and only iff both data streams are reflected back to some common point in space and recombined. If the initial transmission is at time T0, and the first reflection happens at time T1, then the recombination cannot happen until T1+(T1-T0). I'm not sure if this is 100% analogous to what is being done in this paper (the math is kinda furry) but I'm pretty sure it's close.
I don't believe the Star Trek analogy was correct. In the episode, Scotty had his pattern repeat in some sort of cycle that kept his pattern safe. He didn't send himself to a specific point in time, he could have pulled out of it at any point. In fact, his crewmate died because he wasn't pulled out soon enough and his pattern degraded.<p>Scotty in the transporter was more like stasis and not a teleport to the future.
Ugh, typical poor science journalism strikes again. Quantum entanglement can absolutely <i>not</i> be used to transfer information. Two problems are you can't travel faster than light, information included, and second is measuring the spin of an entangled particle only works if you know the state of the other one.<p>So no, you cannot transmit encyclopedias of data using quantum entanglement.<p>As for the rest of the story, it sounds like entanglement can work across time. Flipping the state in the past instantly flips it in the future. However, in either direction of time the observer already knows the state so no info transfer, no causality breakage.