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.

learn more… | top users | synonyms

0
votes
2answers
87 views

Entanglement of Tripartite States

Is there any simple algorithm to determine the entanglement of a tri-partite state? In particular, what is the proof for entanglement of $ |GHZ\rangle $ and $ |W\rangle $ states? $ |GHZ\rangle =\...
3
votes
1answer
483 views

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 fine-tune the ...
0
votes
1answer
61 views

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 ...
2
votes
1answer
99 views

Is entanglement a classical phenomena (2)? [closed]

The answer to this question seems to be yes, because you can simulate it with a classical computer and thus by a local classical theory (rule 110 CA) (see this question). However most people ...
3
votes
2answers
1k views

Can cellular automata be reconcilied with quantum mechanics?

CAs are deterministic representations of the universe, which, according to the Bell's inequality are not entirely accurate. Cells interact "locally" (only with the closest neighbours), while quantum ...
1
vote
0answers
21 views

Creation of a non-maximally entangled photon state

I'm reading a paper on testing the Bell Eberhard Inequality. The experiment performs polarization tests on states of the following form: $|\Psi_r>=\frac{1}{\sqrt{1+r^2}}(|HV>+r|VH>)$, where $...
0
votes
1answer
153 views

Doesn't the concept of “hidden variables”, by definition, encompass all possible results? [closed]

While i don't know all the mathematical/experimental specifics i know enough about entanglement/bell's theorem to know the general ideas of what's going on. It's definitely interesting but i'm not ...
2
votes
1answer
109 views

Entanglement and the uncertainty principle

Suppose you have two maximally entangled particles. You measure the spin about the x axis of the first and the spin about the y axis of the second. But both spins cannot be known simultaneously, so ...
-1
votes
1answer
54 views

Question regarding entanglement

Could the paradoxical nature of entanglement be the result of a change in the nature of quantum properties, or an incomplete understanding of such, instead of non-locality?
1
vote
0answers
198 views

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 ...
1
vote
0answers
74 views

The “spooky action at a distance” and reference frame

It is often said that the measurement in EPR experiment is instant, as somehow described as "spooky action at a distance". However, the notation of equal time depends on reference frame, according to ...
3
votes
0answers
206 views

Is This A Working Time Machine? [duplicate]

picture taken from this video for those who do not like to click on youtube links youtube video - retrocausality through Double Slit & Bose The answer will probably be no, but i am interested to ...
1
vote
2answers
142 views

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 ...
7
votes
3answers
2k views

What is quantum entanglement?

What is quantum entanglement? Please be pedagogical. Edit: I have updated my background under my profile.
3
votes
1answer
111 views

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? ...
3
votes
0answers
92 views

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 ...
-3
votes
2answers
405 views

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 ...
1
vote
1answer
103 views

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 ...
2
votes
1answer
163 views

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 $\frac{...
1
vote
1answer
87 views

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 ...
-1
votes
2answers
198 views

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 ...
0
votes
1answer
63 views

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: ...
0
votes
2answers
168 views
1
vote
2answers
416 views

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 ...
0
votes
1answer
90 views

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 ...
8
votes
5answers
4k views

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 does?...
3
votes
2answers
457 views

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 ...
11
votes
3answers
1k views

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 ...
13
votes
4answers
2k views

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 ...
4
votes
2answers
427 views

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 ...
2
votes
2answers
217 views

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 ...
0
votes
1answer
98 views

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, ...
-1
votes
4answers
202 views

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 "...
-2
votes
1answer
220 views

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 - ...
5
votes
3answers
1k views

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?
4
votes
1answer
458 views

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 ...
2
votes
3answers
954 views

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 (...
0
votes
1answer
120 views

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, ...
5
votes
3answers
419 views

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 ...
7
votes
3answers
517 views

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 ...
0
votes
2answers
121 views

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 ...
1
vote
2answers
177 views

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 +, ...
2
votes
1answer
90 views

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 ...
-3
votes
1answer
709 views

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 ...
3
votes
1answer
85 views

Are all properties entangled when one property is entangled?

When one or more particles are quantum entangled by say their spin property, do their other measurable properties (e.g., momentum, polarization, whatever?) become entangled as well?
4
votes
6answers
638 views

Explanation for the EPR-like paradox

I am trying to understand the process of Quantum Entanglement for use in Quantum computers. The problem I have is this: Suppose some nuclear process emits an electron-positron pair. Now after ...
17
votes
4answers
2k views

Is there an intuitive description of vacuum entanglement?

People often refer to the fact that the vacuum is an entangled state (It's even described as a maximally entangled state). I was trying to get a feeling for what that really means. The problem is ...
1
vote
3answers
94 views

How are Superposition and Entanglement related?

How are Superposition and Entanglement related? I don't know much of Quantum Mechanics. I am CSE student and got started with this Quantum Computing. It is interesting! If anybody can help me on this,...
4
votes
3answers
163 views

Is there a unitary, linear bijection between (1) Maximally Entangled and (2) Factorizable States?

Pretty much as the title says. I am interested in the two particle system, each particle having two dimensional quantum states; naturally if there is a generalisation I'd be interested in that too. So,...
0
votes
2answers
1k views

What's the Cause of Quantum Entanglement? [duplicate]

What is the cause of quantum entanglement? When two particles become entangled what property of them basically changes as to establish a link between them and how the information is exchanged between ...