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## Faster than light information travel

 Quote by JohnLuck A) It is not obvious to me that filtering breaks entanglement. It depends on whether the filtering interacts at all with the photons that pass through it. Do you know the properties of all types of polarization filters?
All polarization filters place the photons into an eigenstate, if they do not do that then they are not filters. Entanglement only happens when the state is a superposition of eigenstates, so it is self-contradictory to claim that you have placed a pair of photons in an entangled eigenstate.
 ... I... just... Wow. Well, good luck with breaking physics. I'm out.

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 Quote by JohnLuck B) You are wrong. Measuring the angle B would set the angle A at random for all the photons. This is what is so special about entanglement, the entangled pair affect each other instantaneously over a distance, (Einstein called it "spooky action at a distance"). I suggest you read up on it. Also what did you think entanglement was?
You are being unnecessarily rough with this comment.

The fact is that your idea does not transfer any useful information faster than light. All outcomes appear completely random regardless of the angle you select to measure, and regardless of what you do elsewhere. No pattern emerges until and unless you compare Alice's result with Bob's. That requires a traditional information channel operating no faster than c.
 (Apologies DrChinese, I just saw your response.) JohnLuck, would I be right in thinking the you want to use the machine to send information faster than light? If so, my understanding is that this is not possible. (Geogir / DrewD / DrChinese, you seem like you could you confirm / refute this ... please?) The only way to decript the "message" is to follow up with a letter / phonecall to explain to the Martian how the key to the message (which will change with every message) works. Otherwise the Martian only knows the the answer to the question is yes / no (0/1), not what the question is. And you can't agree the question in advance, because until you measure your particle, you don't know if it needs to be positive or negative. I'm no expert on this, just a reader like yourself, but I hope that this helps. Regards, Noel.

 Quote by georgir ... I... just... Wow. Well, good luck with breaking physics. I'm out.
Sorry, my reply was worded unnecessarily arrogant sounding. What I meant was something like "What is your understanding of how entanglement works?" It was not meant to be so condescending.

 Quote by DaleSpam All polarization filters place the photons into an eigenstate, if they do not do that then they are not filters. Entanglement only happens when the state is a superposition of eigenstates, so it is self-contradictory to claim that you have placed a pair of photons in an entangled eigenstate.
This is probably why it wouldn't work then! My machine would require us to only send photons with a certain spin and the receiver to know about this default spin. If there is no way to do that, then certainly there is no way to send information using this. So I guess this is solved.

Your No. 1 might be wrong. The problem is that thinking about what's happening in terms of an underlying polarization doesn't (re Bell, etc.) work. It's true that if the polarizers are aligned, then given a qualitative result at A, then the time correlated result at B can be deduced. Depending on the experimental preparation this might mean that if the result at A is a detection, then the result at B is a nondetection, or that if the result at A is a detection, then the result at B is also a detection. The problem is that this doesn't necessarily tell us anything about the underlying polarization. It also doesn't tell us if modelling the situation in terms of an underlying polarization is correct. The results of Bell tests seem to suggest that this is not the correct way to model entanglement, because Bell tests involve polarizer orientations other than alignment. In other words, if you assume that the entangled particles are identically polarized or oppositely polarized, then a model (at least a Bell type model) based on that will not produce entirely accurate predictions. So, apparently, this sort of classically based conception of quantum entanglement is inadequate to explain the essence of quantum entanglement.

Or maybe it is, and that's part of the ongoing discussion regarding the meaning of Bell's (and similar) theorems regarding quantum entanglement.

For now, it remains an intriguing mystery. But so far there's no indication that any sort of faster than light info transfer is happening.

As a previous poster indicated, maybe the essence of quantum entanglement is related to the empirical Malus' Law -- the qualitative foundation of which is unknown, but which doesn't seem to suggest any sort of faster than light phenomena.

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