Quantum entanglement is the mechanism by which quantum correlations between two sub-systems survive even after being physically separated from an interaction region. The correlations could in principle survive without neither time nor space constraint.

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Is there a fundamental interaction responsible for quantum entanglement?

Quantum entanglement seems to share information between particles instantaneously, as well as characteristics of these particles through changes that occur in each particle. If forces transfer energy ...
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What is quantum entanglement?

What is quantum entanglement? Please be pedagogical. Edit: I have updated my background under my profile.
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Evolution of Eigenstates when two spin systems are coupled

I would like to describe the following situation: We have two spin systems: Spin 1 ($S_1$) and Spin 1/2 ($S_2$). Now imagine you somehow change their interaction so that you can finetune the ...
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Bell inequality with triplet state

Is it possible to prove Bell inequality starting from a state formed from triplet states, i.e. $\frac{1}{\sqrt{2}}(|\uparrow>_A|\uparrow>_B+|\downarrow>_A|\downarrow>_B)$? If not, why? ...
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Local EPR-experiments with photons in vacuum?

The principle of non-locality states "that an object is influenced directly only by its immediate surroundings." (Wikipedia) When two entangled particles are measured in an EPR experiment, we ...
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Geometric measure of entanglement for fermions or bosons?

For a system consisting of multiple components, say, a spin chain consisting of $N\geq 3 $ spins, people sometimes use the so-called geometric measure of entanglement. It is related to the inner ...
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Could Quantum Entanglement be related with gravitational interactions? [closed]

Particles are entangled when they share the same state and their properties become correlated. Interaction with one of them, by say measurement, is experienced instantly by the other. If we measure ...
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Entanglement, Bohr-Einstein Debate, Bell's Inequality

On BBC episode The Secrets of Quantum Physics (Part 1) Jim Al-Khalili explains quantum mechanics for the layman. In the first half, he does a very good job; in the second half, either he thought his ...
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Entanglement ladder algebra and quantization of entanglement

Usually in QFT, even optical quantum mechanics papers, usually resort to describe n-states in terms of the ladder algebra, plus a parameter for polarization, but the entanglement information is ...
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How to understand the entanglement in a lattice fermion system?

Topological insulator is a fermion system with only short-ranged entanglement, what does the entanglement mean here? For example, the Hilbert space $V_s$ of a lattice $N$ spin-1/2 system is ...
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Is entanglement a classical phenomena?

If I have an entangled state shared between two parties Alice and Bob $$\frac{1}{\sqrt{2}}|00\rangle+\frac{1}{\sqrt{2}}|11\rangle....(1)$$ then the reduced density operator of Alice's side is ...
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Quantum Entanglement

My book is generally being quite unclear about something. So firstly I know that if the system is not entangled, we can write its state as $|ab\rangle=|a\rangle|b\rangle$ (if we understand the ...
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How was it proven that a quantum entanglement measurement of particle A, affects properties of particle B

If I understood the wikipedia article correctly, quantum entanglement claims that information travels instantly between entangled particles. An act of measurement on one of the entangled particles ...
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Why is quantum entanglement considered to be an active link between particles?

From everything I've read about quantum mechanics and quantum entanglement phenomena, it's not obvious to me why quantum entanglement is considered to be an active link. That is, it's stated every ...
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Is teleportation possible?

When I just learned about quantum entanglement, I read that if two electrons are in quantum entanglement and placed in two different places, the photon which interacted with one electron is teleported ...
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Does a normal torch emit entangled photons?

I was reading a sciencenews.org post about three photons being entangled. My question here is, why is the chance of producing an entangled pair once in a billion times? Isn't every particle produced ...
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Particles interacting with distance invariant force [closed]

What happens if you have a bunch of particles interacting with distance invariant force between them? I was thinking about it in terms of slit experiments and quantum entanglement. Just say for ...
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What does inflationary theory explain which quantum entanglement cannot?

Introduction This is an honest question... I don't study inflationary theory extensively (This is an understatement) but I am lost as to why it was developed in the first place. Here is why: ...
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Energy transfer using quantum entanglement

Can we transfer energy from one place to another separated by arbitrarily large distances without any time lag? For instance, if Alice and Bob are two observers making measurements having a singlet ...
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Entanglement entropy in (1+1)d field theory with dynamical critical exponent $z>1$

It was well known that for (1+1)d CFT(z=1) case, we can use the tool of conformal map to derive the formula of entanglement entropy for a finite interval: S ~ $c \log L$. L is the length of the ...
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spooky nonlocal communication, or bad abstract?

I'm referring to this recent paper, "Experimental Proof of Nonlocal Wavefunction Collapse for a Single Particle Using Homodyne Measurements" by Fuwa et al. published in Nature Communications. ...
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Why does measuring the spin of an entangled particle cause it to become unentangle?

I've been taught that measuring the spin of an entangled particle causes it to become unentangled, but not how or why, so I'd like to know by what process this occurs. Is the cause known? If so, ...
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Does entanglement not immediately contradict the theory of special relativity?

Does entanglement not immediately contradict the theory of special relativity? Why are people still so convinced nothing can travel faster than light when we are perfectly aware of something that ...
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What laser and BBO are needed to create entangled laser streams?

I have been reading about entangled particles, lasers, the two slit experiment, etc. I really know nothing from physics (i.e. equations, formulas, theory); so please respond accordingly. From my ...
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Does quantum entanglement arise from quantum theory or is it merely an experimental observation?

I assume that entanglement emerges from quantum mechanics because the idea was around before experimental verification (e.g the EPR paper). How then does entanglement emerge from the theory (please ...
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Entanglement, real or just math?

I'm new here, actually this is my first question so I'll just get to it. In quantum entanglement when something acts on one particle the other one reacts also, just in reverse (more or less). From ...
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Faster than light signals and the price to be paid if we accept them : a very simple protocol

Most physicists currently understand entanglement as transferring information instantaneously, yet not violating causality. Is this really a satisfactory explanation, or should be look for something ...
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Entanglement of Mixed Quantum State

As per Wikipedia: Quantum entanglement is a physical phenomenon that occurs when pairs or groups of particles are generated or interact in ways such that the quantum state of each particle cannot ...
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Wouldn't 3 or more particle entanglement allow passing classical information?

My (simple) understanding of entanglement is that by measuring the spin of one entangled particle, the other entangled particles' spin changes to the opposite of measured particle. This act of ...
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Study the center and interior of a black hole using quantum entanglement

Having just watched the latest in a long line of space movies; Interstellar tries to combat the problem of studying the center of a black hole and understanding what's going on inside. My question is, ...
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How do we know that quantum entanglement is instantaneous?

Is it a mathematical certainty demonstrated through some proof or is this simply what observation shows? How sensitive are the measurements that determines the "communication" (I know... It is not ...
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Quantum Eraser thought experiment with light photons of distinct color

I tried to recreate the Quantum Eraser experiment into a thought experiment with a few changes. It left me a little perplexed as to what outcomes I should expect. Any help would be appreciated. Lets ...
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Thought experiment on graviton breaking the speed of light [closed]

The effect of gravity travels at the speed of light. Suppose we can entangle a pair of gravitons (which are only theoretical, but who knows for sure?) and separate them over a vast distance. Hold on - ...
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What is the difference between maximally entangled and maximally mixed states?

To my understanding, mixed states is composed of various states with their corresponding probabilities, but what is the actual difference between maximally mixed states and maximally entangled states? ...
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A naive question about topologically ordered wavefunction?

Topological entanglement entropy (TEE, proposed by Levin, Wen, Kitaev, and Preskill) is a direct characterization of the topological order encoded in a wavefunction. Here I have some confusions, and ...
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Is there any theoretical limit to the distance at which particles can remain entangled?

As for as I understand (which is admittedly very little) particles that are created together become entangled. Currently, the experiments using entangled particles are over relatively short distances ...
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How can quantum entanglement send information?

I don't believe this is a duplication (either that or I didn't understand the answers to the other questions). I understand when sending information via radio waves that the frequency or amplitude is ...
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can we transfer data via quantum entanglement (likewise we communicate today) to a specific target

Today we rely on electromagnetic field for communication. I'm a entrepreneur, I want to know why we can't transfer data with this technology to transfer data from one place to another place. It can ...
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Why is the distance in non-local entanglement for teleportation limited by time

In a recent paper, researchers described a system that can teleport a quantum state without the need for the entangled particles to actually "meet" each other. I'm reading, in particular, ...
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Local explanation of the Aharonov-Bohm effect in terms of force fields

Here is an interesting paper for the Physics SE community: On the role of potentials in the Aharonov-Bohm effect. Lev Vaidman. Phys. Rev. A 86 no. 4, 040101 (R) (2012). arXiv:1110.6169 ...
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Would 2 entangled atoms decay at the same time?

I have a very basic understanding of entanglement and radioactivity. But say 2 uranium atoms are entangled and then 1 of them decays, what would happen? Would the other atom decay as well? Or if not ...
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Quantum Entanglement Versus Inflation in the Early Universe?

Quantum entanglement is one of the most fascinating and mysterious phenomena in nature. It needs no interactions, or any sort of exchange for it to take place. It is possible, not against any rules of ...
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Can entangled particles stay in sync when one of them is travelling near light speed?

Can entangled particles stay in sync when one of them is travelling near light speed? I ask this because it means that time would be experienced at different speeds for both particles and could allow ...
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Entangled Photon (laser pointer)

From a laser pointer emission; is it creating entangled pairs of photon? is it possible to get more than "pair" entangled, like group of photons all entangled?
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Properties of controlled z-rotations

Given n qubit gate of the form c-z-z-z... (shorthand for c-z between qubit 1 and 2 followed by c-z between 1 and 3 and so on up to n qubits) it seems to be possible to find local unitaries which will ...
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Spin Control and Entanglement

I have a thought-experiment sort of question and I don't know where to start. Suppose you have an entangled pair, e1 and e2, and you split them. Then BEFORE reading them, you spin control e1 to +, ...
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An error in my understanding of entanglement

Based on my knowledge of quantum entanglement, I can set up a scenario which leads to a contradiction with the No-communication theorem. Please help me find the flaw. Suppose Alice wants to ...
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Does this experiment on wave-particle duality and complementarity disprove quantum mechanics and prove the EPR viewpoint on it?

I recently read Photons act like they go through two paths, even when we know which they took, at Ars Technica, which reports on the paper Wave-particle dualism and complementarity unraveled ...
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What Quantum Entanglement is NOT? [closed]

What are the most insightful experiments on Quantum Entanglement undertaken in the last few years showing what it is not? What insights did we gain from does constructive failures? Is there a current ...