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My understanding of entanglement is that causality is not violated because while taking a measurement of an entangled particle, while you do gain information about the particle it is entangled with (due to conservation of angular momentum), you cannot affect the outcome of the measurement directly without also influencing the entangled particles in such a way that would collapse the quantum system. In other words, if the spins of two entangled particles were measured in different locations, while you would learn information about both particles at the same time (regardless of locality), because there is no way to potentially know more about the spin of the particle before measuring it than the probability it will be in a given state (and no way to influence the probability of a given measurement that wouldn't also affect/collapse the entangled state), there is therefore no way to send information faster than the speed of light via entanglement.

This is my understanding, and please feel free to correct me if it is in any way flawed. But if all this is correct, there is a somewhat interesting conclusion you can derive from this information.

So say Alice is in outer space, in some sort of futuristic spaceship, approximately one light year from earth. Before leaving earth, Alice and Bob created 1,000,000 pairs of entangled photons (for good measure), and Bob kept half the entangled photons on earth, while Alice took her half aboard her spaceship. She also took an atomic clock with her, and they both agreed to measure the states of their entangled photons exactly one hour (relativistically speaking) apart, once Alice had reached the distance of one light year from earth. Through painstaking physical isolation, the quantum states of all entangled photons had been preserved in such a way, so that with their highly accurate measuring equipment, the statistical probability that any one given photon would measure up or down, was within almost complete statistical certainty, 50%. Well, let's say with a 0.1% margin of error. This statistical margin of error, had been rigorously proven, and all variables had been accounted for, to the point that if even 50.2% of the measured particles were definitively measured with the same spin, something interesting must have occurred.

Now let's say Bob had a little trick up his sleeve. Let's say that Bob's measuring equipment allowed him to take measurements with Planck scale accuracy, and through exhaustive testing, he had discovered a method to stage the timing of his measurements, so there was a slight bias toward measuring an up or down spin that had no bearing on the quantum system until the exact moment of measurement. A sort of hidden resonance that correlated the results of his measurements with time. So when Alice goes to take her measurements, and notices a bias in her data toward measuring a down spin of 0.2%, she knows Bob must have staged his measurements to have a bias toward measuring an up spin, and Alice and Bob have successfully communicated information faster than the speed of light.

This scenario of course hinges on the assumption that the state of the quantum system is influenced by time (that the entangled photons are in a real sense oscillating between two states in time), rather than staying in a completely static state until measurement. If such were the case there would be nothing Bob could do time wise that would influence the results. So the obvious question here is, do we know if entangled photons experience time? If not, I'm not sure what the implications are exactly, but it seems at least to be an interesting observation. But what if they did experience time, in such a way that time could affect the results of the measurement?

Well, in this case, we have a conundrum. Unless the state of the quantum system has no correlation with the timing of observation whatsoever (true randomness), then it is at least theoretically possible to exchange information faster than light. Even the slightest, most minute correlation would be sufficient to violate causality if measurements were precise enough. The problem with this observation, is that nothing can be proven to be random. If you observe a phenomenon for any given finite amount of time, and observe no discernible pattern whatsoever, there will always be a non-zero possibility of a pattern eventually emerging. No amount of observation is sufficient to rule out this possibility. Therefore, you must come to the conclusion that causality cannot be preserved without a source of true randomness, but that it is also impossible to prove that true randomness exists.

I'm really not sure what to make of this, does anyone here have thoughts? Keep in mind my lack of background in physics, so fancy mathematical symbols and terminology will probably be lost on me. ^^;