All Questions
Tagged with non-locality quantum-information
31
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How do non-local correlations occur in QM without a cause? [closed]
The Copenhagen interpretation of QM ultimately amounts to asserting that non-local correlations occur without a cause since that cause would involve propagation of information faster than the speed ...
user398827
2
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1
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Quantum Mechanics without Complex Numbers in a multipartite setting
I was fairly convinced that usual QM formalism didn't necessitate the use of complex numbers and that ultimately they're just a matter of convenience and utility rather than anything fundamental. This ...
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Can a point in the quantum set of correlations violate more than one independent facet Bell inequality?
Usually, depictions of the quantum set of correlations and the local polytope look something like:
In this image it looks like non-local points belonging to the quantum set (in yellow) violate only ...
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What is the difference between nonlocality and entanglement?
I'm a bit confused about the difference and relation between (quantum) nonlocality and entanglement.
To give some context about my confusion, I was reading this paper: Brunner, Nicolas, et al. "...
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In the Bell CHSH experiment, why are Alice and Bob not allowed to pre-arrage their measurements?
From Nielsen and Chuang, Chapter 2:
Imagine we perform the following experiment, illustrated in Figure 2.4. Charlie prepares
two particles. It doesn’t matter how he prepares the particles, just that ...
- 508
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How are the different derivations of Bell's inequality related?
I wanted to ask about two different derivations for bell's inequality for the known CHSH inequality.
One derivation is the one bell originally used in 1971
this derivation is thoroughly written in ...
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What is wrong with violation of locality (EPR paradox)?
When studying the EPR paradox, at some point we must resign ourselves that Reality and Locality can not be both true in the current theory of quantum mechanics.
A lot has been said in Physics.SE about ...
2
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Where does the negative cosine relation for quantum mechanical CHSH correlations come from?
I have been lately looking into Bell's inequality. I have noticed a recurring graph that depicts the correlation of two spins when measured at different angles, for the quantum and the classical case:
...
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Are violations of realism the same thing as contextuality?
I am basically looking for a counter-example where we'd get contextuality but not violations of realism (and vice-versa). If no such counter-examples exist, then it seems to me that they're really one ...
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If quantum entanglement causes the violations of Bell's inequality why don't we see perfect correlation?
From wikipedia:
For example, if a pair of entangled particles is generated such that
their total spin is known to be zero, and one particle is found to
have clockwise spin on a first axis, then the ...
- 870
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How does quantum contextuality relate to realism?
According to Spekkens contextuality can be defined as follows:
Suppose A, B and C are Hermitian operators such that A and B commute,
A and C commute, but B and C do not commute. Then the assumption ...
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2
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2
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How does relaxing counterfactual definiteness allows for CHSH inequality violation?
Scenario, I want to play a game with a group of students as a teacher, I ask two teachers to help.
The students are from the central classroom, going to room A and room B where the teachers there asks ...
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A Venn diagram for: (non-)locality, (non-)realism, (non-)contextuality, (non-)signalling, (dis-)entanglement
I recently asked a (yet-unanswered) question about the relationship between state-dependence and violations of realism. The more I read on the subject, the more I find myself digging deeper in a ...
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How can a disentangled state be contextual?
I (re-)learned about Bell tests from the ground up based on this very intuitive lecture by Spekkens. In a nutshell, realism is violated whenever measurement statistics cannot be reproduced by ...
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Concrete Example of Quantum Entanglement, Quantum Steering and Bell Nonlocality
I was reading the wikipedia page for quantum steering. The following is the mathematical way they have described the three notions:
Is there any concrete example of these three concepts? Like, any ...
