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Entanglement experiment performed in one frame of reference guarantees that the two measured results are synchronized in this frame of reference. If we try to perform the same entangled experiment while the two ends of the same length fiber optic lines are attached to two frames of references moving with a constant relative velocity, the two measured results ...


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I'm not sure your question is as well posed as you think it is. In order to be 100% sure to have an entangled spin state, one would have to measure it, but can entangled states be eigenvectors of Hermitian operators (= results of measurements) other than the trivial one? If you know something is in one of various orthogonal states then in principle the ...


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No. The particles have a joint spin state, $\left|\uparrow \downarrow \right\rangle - \left|\downarrow \uparrow\right\rangle.$ When you send the left particle through a Stern-Gerlach device then the device changes from $\left|0\right\rangle$ to $\left|1\right\rangle$ when the left particle is detected as down. So $\left(\left|\uparrow \downarrow ...


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Imagine you have a pair of coins. Whenever you throw them, each of them is fully random, but their outcomes are opposite. Now imagine you throw the two coins. You look at the left coin. When it is head, you discard both coins and start again, when it is tail, you keep it. Since you have never looked at the right coin, it should still be completely random. ...


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No. The other photon might even be forbidden to produce a pair over by itself all by itself since there might be no nucleus over by it. The other photon doesn't have to copy what the first one does. But many things could happen to the entanglement. And that is partly because there are many ways the photons could have been entangled. For instance, you could ...


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No. Being entangled does not mean they mirror everything the other does. It only means certain properties are in an inseparable state. Destroying one of the pair would end this state


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I did not go to details of Page's work. I think what's important is how to understand his result. I tried a simple simulation of the information transfer during black hole radiation with a simplified black hole constructed by collapsing EPR pairs. Then I have a similar curve of information/entropy change during the black hole radiation. I have to say it's ...


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The short answer is yes, in quantum mechanics quantum non-locality refers to the apparent instantaneous propagation of correlations between entangled systems, irrespective of their spatial separation. In quantum field theory, the notion of locality may have a different meaning, as pointed out already in a comment. Details: The notions of locality and ...


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An important thing to understand is that Bell's Inequality is about how certain (incorrect) theories make predictions. It tells you absolutely nothing about other theories, not matter how similar the theories sound. For instance Ball assumed that there is a hidden variable that combines with the orientations to tell you the results but that the hidden ...


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I found the answer to my question on the Bell's theorem Wikipedia page: With the measurements oriented at intermediate angles between these basic cases, the existence of local hidden variables could agree with a linear dependence of the correlation in the angle but, according to Bell's inequality (see below), could not agree with the dependence predicted ...


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Your mistake was thinking each particle has a state. If that were the case they would not be entangled. What happens is you have a joint state for the pair of particles. Since it starts out a joint state, when you act on the state you act on a joint state so it affects the joint state. And yes, what we call an observation or a measurement changes the ...


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The diagram of the experiment has a large box bearing the legend "coincidence counter". The experiment is measuring fringes in the probability of a match in the photons' location. The probability for each individual photon to arrive at a specific place is not changed by different measurements. The probability of a match in location when the results are ...


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The entanglement is always based on pair production of the involved particles. And all thoughts about faster-then-light evaporates to dust, if one understand that the entangled parameters are given at the moment of the pair production. At the moment, we measure the entangled parameter from one of the particles our unknowledge about the parameter collapses. ...


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I'm still not certain I understand things correctly, but I'll answer my own question with my current understanding. There are different types of multi-particle quantum entangled states; GHZ is one of them. The proposed scenario with GHZ would NOT work. It mistakenly assumed that after one particle is measured, the other two would measure the opposite ...


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I am not sure I agree with the statement that this is not possible. Here is my scenario. We have two space explorers who both set off from Earth at the same time. Their destination is in opposite directions. The travel at the same speed. When they set-off from earth, at that time, a beam of entangled electrons are generated. One particle is transmitted ...


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The title of the article and the abstract of the article both say it is entanglement swapping and you described entanglement swapping, so it seems like entanglement swapping. The authors also mention that one interpretation is the measuring the first particle on the first entangled pair steers the dynamics of the second pair. In fact, this is normal, if you ...


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First off, I want to point out that the word communication is a bit misleading. You cannot communicate information through quantum entanglement (No-communication theorem) If you try to measure the properties (spin) of, say, an electron $$|\psi_{electron}\rangle = \alpha |\uparrow\rangle + \beta |\downarrow \rangle, $$ you have the probability of measuring ...


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No. Wormholes do not play a role in entanglement. In fact, entangled particles don't 'communicate' in the usual sense; instead, they show nonlocal correlations which can sometimes exceed what you'd expect from, say, a pair of boxes containing socks of different colours. What Einstein got wrong wasn't the 'spooky', it was the 'action' - neither particle acts ...


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Classical variables allow for correlations that are like quantum and not only linear : Bell's Ansatz is $$C(A,B)=\int A(\theta_A,\lambda)B(\theta_B,\lambda)\rho(\lambda)d\lambda$$ Suppose $$A(\theta_A)=2\Theta(\lambda-\theta_A)-1,B(\theta_B)=2\Theta(\theta_B-\lambda)-1$$ And $$\rho(\lambda)=sin(\lambda)/2$$ Between There you see that the correlation gives ...


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that two entangled particles have opposite characteristics that is kept regardless of distance: e.g. if one of them is detected to have a up spin then other is bound to have a down spin. Firstly: as your description shows, the relevant correlation is pair by pair. It must be (ideally) unambiguous whether a given detection indication of the one analyzer ...


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One way to facilitate this discussion is to think of what's classically forbidden but quantumly permissible. My favorite so far is a game that I call Betrayal. Let me explain that in this answer. Betrayal: Game Rules The players are a cooperative three-person team, they will either all win or they will all lose. They will be put through some number $N \gg ...


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I still don't quite understand the reasoning behind the conclusion that entangled particles somehow can communicate their state to each other instantaneously, even though they are separated by a substantial distance This isn't correct, they occupy a joint state. From what I gather [...] upon observation of one of the particles, it immediately (and ...


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Entanglement is the term used for quantum mechanical correlation, and as always "correlation does not mean causation". In quantum mechanics most yes/no correlations come from conservation of quantum numbers. Conservation laws are strict as for example angular momentum conservation. If two electrons are set up to have spin up and spin down, the total spin ...


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It does seem like you have some misconceptions. You don't have to measure them simultaneously, in fact the whole idea of "being simultaneous" turns out to be subjective and observer dependent in relativity. But the real issue is that there are many measurements you can do. For instance you could measure the z component of spin, or you could measure the y ...



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