# Tag Info

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Do you think that quantum predictions succeed perfectly ? not only it is possible to trace the $cos(\Delta \alpha)^2$ curve with hidden variables but some clean simulations can do better than most of the experiments, with whom they share many flaws to the point that one may wonder if they are defects. But, the negations must be constructive and the ...

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How by citing a statistical correlation, we can say "instantaneous action at a distance" is necessary. Suppose that there is a challenge which a simple argument establishes can only be solved by a classical probability distribution with 75% effectiveness, but which a quantum team of players (i.e. a team with access to a shared quantum state) can solve ...

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tl;dr: Your points 1 to 5 are misunderstandings. The answer to your question follows from a better understanding: Entanglement is no active link, hence there is no need for instantaneous action. However, if you want a certain kind of ontology, then you must accept a certain kind of instantaneous action/non-locality (which doesn't necessarily violate ...

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The physical description of what Bell's inequality is about is as follows. Suppose that the outcomes of measurements are described by stochastic variables. That is, each quantity has a value that is some number picked at random in some way. And suppose that for each system the quantities influencing how the numbers are picked are determined locally. That is, ...

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Quantum Entanglement of Lee and Ron I'm afraid we have no evidence that Lee and Ron are in any way entangled. Lee and Ron are born as perfectly identical twins except for Lee being left handed and Ron being right handed. Years after birth they are seperated, Lee moving to Latvia and Ron moving to Rwanda. At one time they are both writing but ...

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(1) Quantum mechanics predicts 25% or more will correlate. (2) Bell says hidden variables should correlate 33% or more of the time. (3) The difference between the two is Bell's inequality. (4) They are different things unless I misunderstand your question. Two objects are entangled if you can measure or observe one of them and instantly know something about ...

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I think the answer to my first question is no: Let's say A and B are detectors. Each has two states: |detected> and |not detected>. Then we will have: Ψ′up∣up⟩|A detected>|B not detected> + Ψ′down∣down⟩|A not detected>|B detected> Both spatially separated parts of the wave function entangle with both detectors. (Normalization is suppressed for ...

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If B released energy when A was measured, you could use it for communication. And you know the answer to "Can entanglement be used for communication?" is NO. You mentioned it in your question! Therefore... No, entangled particles don't release energy when their partner is measured. They don't change in any locally determinable way when their partner is ...

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If the particles are nontrivially entangled, then particle $A$ cannot be in an eigenstate of the energy operator (or any other operator that acts just on $A$'s state space) in the first place. If the initial entangled state is, say, $X\otimes Y+Z\otimes W$, where (for example) $X$ and $Z$ are energy eigenstates, then an observation of particle $B$ will ...

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It's interesting you are asking this question. Just few days ago an article was published in the Quanta Magazine discussing precisely this issue. There it goes beyond what you call “the usual quantum mechanics description of entanglement”. In the new theory, the quantum entanglement (QE) is applied not just across the space but also across the time. By ...

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You are absolutely right with the cards. To lift the entanglement on atomistic level talented physicists created the spontaneous parametric down conversation. They solved the task to create pairs of particles (photons) with one entangled parameter. Often this parameter is the direction of the electric field component of the two involved photons. This ...

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Under what circumstances could particles become entangled without our intervention? How frequent would that have happened in the various stages of cosmic expansion? Is it possible that particles may have been entangled in early cosmic history and remain so today? The fact that two particles interacted at some point in the past doesn't mean they are ...

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Yes, particles become entangled without our intervention all the time. However, it isn't relevant because of the monogamy of entanglement. What monogamy of entanglement means (intuitively) is that a particle can have a large amount of entanglement with one, or maybe two, other particles, but it can only have a little bit of entanglement with each of many ...

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I'm afraid that the recent emphasis on quantum information theory has muddied the waters for many about what entanglement really is. Entanglement is any circumstance where two or more spatially indistinguishable particles interact and either maintain that interaction or spatially separate and fail to interact with other quantum systems. Count the number of ...

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When entangled photons are created in Bell-type experiments, it is their polarizations which are entangled. It is not clear to me that their positions or momenta are entangled in the same way. But anyway, engtanglement does not violate "no action at a distance" and in particular there is no way to see at location S1 what measurement is being made at location ...

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Most importantly, the pattern detected at S2 will not depend on the detector D1. Otherwise, this could be used for faster-than-light signalling, which is impossible within quantum mechanics. Beyond that, what you will see at S2 will depend on which degree of freedom has been entangled. Generally, one would expect to see an interference pattern, but if you ...

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