Questions tagged [non-locality]
The non-locality tag has no usage guidance.
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Why are infinite order Lagrangians called 'non-local'?
And in what sense are they 'non-local'?
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Are fermions intrinsically non-local?
Background:
When one studies quantum mechanics of more than one particle, one learns that all fundamental particles can be classified as either bosonic or fermionic. Fermions have a spinor structure, ...
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Bell polytopes with nontrivial symmetries
Take $N$ parties, each of which receives an input $s_i \in {1, \dots, m_i}$ and produces an output $r_i \in {1, \dots, v_i}$, possibly in a nondeterministic manner. We are interested in joint ...
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Locality in QFT vs "non-local" in QM
In quantum mechanics (QM), teacher always emphasizes on the "weird" parts, like EPR paradox, Bell inequality and so on. The Bell inequality tells us that QM is either nonlocal or non-realistic or both....
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Why can't noncontextual ontological theories have stronger correlations than commutative theories?
EDIT: I found both answers to my question to be unsatisfactory. But I think this is because the question itself is unsatisfactory, so I reworded it in order to allow a good answer.
One take on ...
Mateus Araújo
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How to understand locality and non-locality in Quantum Mechanics?
What actually is the definition of locality and non-locality?
Does non-locality in Quantum Mechanics mean however far you separate 2 entangled atoms in space, the 2 atoms can still influence each ...
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Local versus non-local functionals
I'm new to field theory and I don't understand the difference between a "local" functional and a "non-local" functional. Explanations that I find resort to ambiguous definitions of locality and then ...
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What is a local operator in quantum mechanics?
In quantum mechanics, what exactly is meant by "local" operator?
What about a "global" or a "non-local" operator? Are these the same?
Can you also also help me understand what exactly is a local ...
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Is this field redefinition for free scalar field theory non-local?
The action of free scalar field theory is as follows:
$$
S=\int d^4 x \frac{\dot{\phi}^2}{2}-\frac{\phi(m^2-\nabla^2)\phi}{2}.
$$
I have been thinking to redefine field as $$\phi'(x)=\sqrt{m^2-\nabla^...
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CHSH violation and entanglement of quantum states
How is the violation of the usual CHSH inequality by a quantum state related to the entanglement of that quantum state?
Say we know that exist Hermitian and unitary operators $A_{0}$, $A_{1}$, $B_{0}$...
Earl
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What's wrong with the square root version of the Klein-Gordon equation?
The Wikipedia article has a derivation of the Klein-Gordon equation. It gets to this step:
$$\sqrt{\textbf{p}^2 c^2 + m^2 c^4} = E$$
and inserts the QM operators to get
$$\left( \sqrt{ (-i \hbar \...
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How exactly does the proof of Bell's theorem fail if you remove the locality assumption?
In this paper Bell derives his famous inequality using the assumtions of locality and realism. In order to understand how the locality assumption affects the derivation of the inequality, and why it ...
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The derivation of fractional equations
Recently I saw some physical problems that can be modeled by equations with fractional derivatives, and I had some doubts: is it possible to write an action that results in an equation with fractional ...
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Don't these experiments suggest that locality has to be abandoned in the quantum realm?
First a quick recap because maybe my understanding/assumptions are flawed (you can jump to the question highlighted in bold below if you like to):
Bell's inequalities require that an accurate(ly ...
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Why would classical correlation in Bell's experiment be a linear function of angle?
Sorry if it's a newbie question, but I have trouble understanding the following part in the Wikipedia's explanation for the Bell's theorem:
With the measurements oriented at intermediate angles ...
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