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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What is meant by a local Lagrangian density?
What is meant by a local Lagrangian density?
How will a non-local Lagrangian look like?
What is the problem that we do not consider such Lagrangian densities?
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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
$$\left( \sqrt{ (-i \hbar \...
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Definition of Local Function
Now a days I am studying Srednicki's QFT book. In its third chapter it is written that
Any local function of φ(x) is a Lorentz scalar, [...] .
Now my question is: What is a local function?
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Delocalization in the square root version of Klein-Gordon equation
In this Wikipedia article a relativistic wave equation is derived using the Hamiltonian
$$H=\sqrt{\textbf{p}^2 c^2 + m^2 c^4}$$
Substituting this into the Schrödinger equation gives the square root ...
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Bell's theorem and fluid-mechanical experiments using droplets: are local hidden-variable theories possible after all?
Recent fluid-mechanical experiments by the groups of Couder in Paris and Bush at MIT, mimic a surprisingly wide range of quantum effects. The essential ingredient of these fluid-mechanical systems is ...
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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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Legendre transform for non-local Lagrangians, or Hamiltonian of non-local Lagrangian and their properties
This is sort of a multi-part question, mostly dealing with how to treat non-local Hamiltonians and how the corresponding properties of Hamiltonians work in a non-local framework. I proposed an example ...
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Local EPR-experiments with photons in vacuum?
The principle of non-locality states "that an object is influenced directly only by its immediate surroundings." (Wikipedia)
When two entangled particles are measured in an EPR experiment, we ...
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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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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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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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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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Are all instances of quantum non-locality problem artifacts of the use of classical concepts in quantum physics?
Consider experiments involving entangled spins, say two-spin 1/2 particles in the singlet state:
$$\left|\psi\right> =\frac{1}{\sqrt{2}}\left[\left|\uparrow\downarrow\right> - \left|\downarrow\...
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Locality of interactions and their high energy behavior
In a classic Georgi review of EFT, I have read the following quote
The result of eliminating heavy particles is inevitably a
nonrenormalizable theory, in which the nontrivial effects of the heavy
...
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