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"Entanglement" is a term describing economically the quantum mechanical state of a system of particles. It is a short hand way of saying : these particles are described by the solution of the Schrodinger equation, with a wave function that can predict the probability of finding the individual particles in a specific (x,y,z) each with specific quantum ...


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In short: No, your reasoning is backwards. The reduced density matrix is mixed because of entanglement and not vise versa. If two systems A and B are in an entangled state, we can no longer separate the state description and write down individual state vectors for system A and B, i.e: $$ |\psi\rangle_A \otimes |\psi\rangle_A $$ Remember that a state is ...


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The answer is simple: measurement causes the wave-functions to collapse. It can be said that one of the fundamental properties that makes Quantum mechanics so strange is the idea of superposition, which is the property that if you have two physically valid descriptions of a state, then it is physically just as valid for a system to be in any linear ...


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What "entangled" means You probably have put too much in your head for the meaning of the word "entangled." Let me fix that for you: Two systems are entangled in quantum mechanics if the results of separate experiments on those two systems display strange correlations when you bring them back together and compare them. Notice that not all correlations can ...


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Though the entangled states are non-local in some sense, they are not non-local in the sense of allowing superluminal transfer of information, by the no-communication theorem and others. There is no force "responsible" for entanglement. In fact, in quantum mechanics, there is no clear notion of such a thing as "force", although you might derive classical ...


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This an emerging line of work. See a complete workshop on that http://benasque.org/2015gil/ The idea is that clocks based on entangled ion traps are approaching precisions of one part in 10^20. For instance Wineland has been able to detect general relativity effects in a lab by just raising one of his clocks just 3cm. The question remains if variation of ...


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The answer is yes and no, but first, let me point out that you cannot "prove Bell's inequality", the whole point is that you violate the inequality in quantum mechanics. Now, let me come to the yes/no part: It's "no, you cannot violate Bell's inequality with this state", if you refer to what according to wikipedia is "the" Bell inequality: $$ \rho(a, c) ...


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I haven't thought about this one before, so here is an approach that will work if you work hard enough at it. Before I begin banging on, point number 1: Should I assume a spin 3/2 system (4x4 Matrix) or an entangled Hilbert space with spin 1/2 and spin 1 (6x6 Matrix)? Unquestionably the latter. It is a bipartite system and its state space is the ...


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Yes. Any interaction! Entenglement is only a quantum version of correlation. Let supose that you have two $\frac{1}{2}$ spins that interact one to another via magnetic interaction. This interaction can produce an entenglement. But this is not the only one. Some Amount of electrons are entangled in a metal due electrodynamic interaction. You can produce ...


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However, IF the entangled states were predetermined, the EPR Paradox vanishes. One cannot prove they were not predetermined, but must rely on Mr. Bells statistics.


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If you are talking about Star-Trek style teleportation, not with our current knowledge. In various articles about the physics of Star Trek, the one thing most physicists genuinely have a problem with is the transporter. Turning 100kg of human into energy and reassembling them thousands of kilometers away with subatomic precision involves handling an awful ...


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You're right that many interactions are very short-range, while gravity tends to act over long distances. However, gravity is not unique in this--electromagnetic forces also die off with $r^{-2}$. It's true that in practice, the intercession of opposing charges tends to screen this interaction, so you often don't see "bare" Coulomb interactions like that. ...


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No idea if applying Fock algebras to the entanglement description would lead to anything "fruitful", I haven't seen any of that. What I've seen is the emergence of Tensor Network Methods in order to describe entanglement of many-body systems. There is the possibility that TNM can be related with holographic descriptions of gravity. Here is an ...


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For $z=2$ there is a study here http://arxiv.org/abs/quant-ph/0404026 in the context of ferromagnetic spin chain. The result is basically $\log L$. Swingle and Senthil argued in http://arxiv.org/abs/1112.1069 that "generally" the violation of area law for EE is at most $L^{d-1}\log L$ where $d$ is the space dimension. However, http://arxiv.org/abs/1408.1657 ...



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