Questions tagged [contextuality]

For questions related to contextuality, as relevant to quantum computing and/or quantum information. Contextuality means that in any theory that attempts to explain quantum mechanics deterministically, the measurement result of a quantum observable depends on the specific experimental setup being used to measure that observable.

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What is the quantum strategy required to win the Magic Squares game

This question is about the Magic Squares game. Links here, here and link here in which two players try to win a game. It's a cooperative game - either the team wins or the team loses. It is claimed ...
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What do noncontextual scenarios with no quantum model represent?

I've been reading the info about contextual scenarios given in this answer, as well as the outline of the main ideas as presented in section II of (Leifer and Duarte 2020). Following the notation of ...
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What type of "local hidden variable" is ruled out when discussing (non)contextuality?

While reading about noncontextuality and the Peres-Mermin square, I encountered the statement that noncontextuality is tightly related to nonlocality à la Bell. For example, (Kleinmann et al. 2011) ...
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How can one show that Alice's and Bob's answers agree at the intersection cells of Mermin-Peres' "magic square"?

This question is along the lines of Problems in understanding the solution for "Mermin–Peres Magic Square Game" How can one show that Alice's and Bob's answers agree at the intersection ...
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How can one define contextuality within the circuit model?

It is in general believed that contextuality is one of the quantum resource that provides the quantum advantage. A context is usually defined in terms of a set of commuting observables. The quantum ...
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Can the Peres-Mermin square be reframed as a statement on the associated conditional outcome probabilities?

As mentioned in this answer, and links therein (assuming I'm understanding correctly), (non)contextuality can be defined as a property of a given set of conditional probability distributions, that is, ...
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Problems in understanding the solution for "Mermin–Peres Magic Square Game"

I am referring to the article Advanced Topics in Quantum Information Theory exercise 4 and to the MS Quantum Kata MS-Quantum-Kata which describes a solution for the Mermin–Peres Magic Square Game. I ...
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2 votes
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How does quantum contextuality relate to mutually commuting observables?

I am trying to get a better understanding of what is the idea behind quantum contextuality. Quoting from the wikipedia page (emphasis mine): Quantum contextuality is a foundational concept in ...
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What does negative probability represent?

"Negative energies and probabilities should not be considered as nonsense. They are well-defined concepts mathematically, like a negative of money." -Paul Dirac The abstract from Photon-phonon-photon ...
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15 votes
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Is it true to say that one qubit in an entangled state can instantaneously affect all others?

When a qubit is measured, there is a ‘collapse of the wave-function’ as a result is randomly chosen. If the qubit is entangled with others, this collapse will also effect them. And the way it affects ...
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Are there any experimental groups currently measuring quantum contextuality?

I work as a theorist with my current research interests in "quantum contextuality". For those perusing the question, this is essentially a generalization of non-locality where we can show a quantum ...
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