For questions on Bell test experiments or Bell's inequality experiments, including but not limited to the CHSH and CH74.
Questions tagged [bell-experiment]
57 questions
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How would a Quantum Computer (network) perform loophole-free Bell tests?
In a simple form, Bell's theorem states that:
No physical theory of local hidden variables can ever reproduce all of the predictions of quantum mechanics.
Bell developed a series of inequalities to provide specific experimental examples to…
agaitaarino
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7
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4 answers
Are there Bell-like violations that can be observed without collecting statistics?
Observing the violation of Bell inequalities, be it in their original formulation, or in the nowadays more commonly used CHSH formulation, involves computing averages of specific experimentally measurable quantities. In the CHSH formulation, these…
glS
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7
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Definition of locality in Bell experiments
Continuing from my previous question on Brunner et al.'s paper (arXiv); so given a standard Bell experimental setup:
where independent inputs $x,y \in \{0, 1\}$ decide the measurement performed by Alice & Bob on quantum state $S$ with outcomes $a,b…
ahelwer
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7
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2 answers
In Bell nonlocality, why does $P(ab|xy)\neq P(a|x)P(b|y)$ mean the variables are not statistically independent?
I've been working through the paper Bell nonlocality (arXiv) by Brunner et al. after seeing it in user glS' answer here. Early on in the paper, the standard Bell experimental setup is defined:
Where $x, y \in \{0,1\}$, $a, b \in \{-1, 1\}$, and the…
ahelwer
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7
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1 answer
Worst Bell inequality violation with non-maximally entangled state?
I'm familiar with CHSH game and the strategy that allows Alice and Bob to succeed with a probability of $$\frac{1+\tfrac{1}{\sqrt 2}}{2}\approx 85\%$$ if they share a maximally entangled state such as $\lvert\Phi_+\rangle$ and use the measurements…
Franklin Pezzuti Dyer
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What are the 2022 Nobel Prize winning papers of Alain Aspect, John Clauser, and Anton Zeilinger, and how do they fit into the timeline of QIS?
The 2022 Nobel Prize in Physics was awarded to Alain Aspect, John Clauser, and Anton Zeilinger for "experiments with entangled photons... pioneering quantum information science".
Presumably there were noteworthy publications of each.
Are there…
Mark Spinelli
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7
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2 answers
What is the no-signaling set and how can it be related to other types of correlations?
The paper Bell nonlocality by Brunner et. al includes a striking diagram on page 7:
This is fascinating to me because it suggests a framework of categorizing correlations that encompasses classical, quantum, "no-signaling", and maybe full…
ahelwer
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7
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3 answers
References examining Bell inequality violations at large distances
Could anyone point to some references examining Bell inequality violations at large distances please?
I see many times, in pop science articles and research literature alike, that the quantum information of the entangled state is transmitted…
psitae
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Bell State 11 not working for parity curve
I am currently writing a script to automate the creation of parity curves for a 2 qubit bell state and then calculate fidelity and proving entanglement from that (inspired by this paper). It was going really well. I am able to run simulations…
thewolfaxe
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Why is $P(1,2)_{\text{same}} = \frac{1}{4}$ and not $\frac{1}{2}$ in Preskill's Bell experiment?
Context:
Three coins on the table. Each is either heads or tails. You can
uncover any one of the three coins, revealing whether it is heads or
tails but then you choose two the other two coins disappear --- you'll
never know whetehr those…
Sanchayan Dutta
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Determining whether $P(ab|xy)$ factorizes in Bell experiments
Continuing from my previous (1, 2) questions on Brunner et al.'s paper (arXiv) on Bell nonlocality.
Again, we have the following standard Bell experiment setup:
where independent inputs $x,y \in \{0, 1\}$ decide the measurement performed by Alice &…
ahelwer
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6
votes
1 answer
Difference between Bell's inequality and CHSH
In this section of the Scholarpedia article on Bell's theorem, the first paragraph comments that Bell's original inequality is not ideal for experimental verification because it requires perfect anti-correlation of the variables, and for that reason…
Pedro
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5
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Choosing operators for maximal Bell-CHSH violation for an arbitrary state
If I have the density matrix $\rho$ for a bipartite system (each system is two-dimensional), what set of observables should I choose so that I obtain the maximum possible violation of the Bell-CHSH inequality?
Say $\rho$ can be written as:
$$\rho =…
Bard
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5
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2 answers
What is an example of an entangled state whose correlations are describable with a local hidden variable model?
When talks about CHSH inequality, we always say that the states that violate the inequality are entangled, while some states that do not violate the inequality can also be entangled.
For the latter case, i.e. for those states which are entangled but…
narip
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4
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1 answer
Simultaneous eigenstate of commuting observables and their tensor product
So this is about something from Preskill's notes on Quantum Computation and Information, Chapter 4, page 3.
Imagine we have a maximally entangled state (Bell state). We can identify the Bell state by measuring the phase and parity bit with the…
CFRedDemon
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