Questions tagged [non-locality]
The non-locality tag has no usage guidance.
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Non-locality of the wavefunction in QM and Twistor theory [closed]
Regarding locality, I don't think locality is a principle per se, but we often assume that the physical fields are local on spacetime, describable by partial differential equations and so on. But of ...
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Bohmian mechanics, Leggett inequality, realism and nonlocality
Very often it is said that the Bell inequality has ruled out the possibility of hidden variables (HV) in QM. This is incorrect since Bell inequality has ruled out local hidden variables: nonlocal HV ...
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EPR effect, non-locality, positivism and realism
In the framework of EPRB experiments, has an experimental verification been performed of the conservation of 2-time correlations of Bob's photons polarization despite Alice's polarization measurements?...
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Relativistic Schrödinger Equation: How is it relativistic and can it be useful? [duplicate]
As is well known, the usual Schrödinger equation,
$$\mathrm{i}\hbar\frac{\partial}{\partial t}\psi=-\frac{\hbar^2}{2m}\Delta\psi+V\psi,$$
is not relativistic. It can be derived formally by applying ...
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Measurable effects of the global structure of the SM
It is known that the Lie algebra of the SM is
$$
\mathfrak{su}(3)\oplus \mathfrak{su}(2)\oplus \mathbb{R}\,,
$$
so that the Lie group is
$$
G_{\text{SM}} = \dfrac{SU(3)\times SU(2) \times U(1)}{\Gamma}...
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How can the quantum state of one particle depend on the other in entanglement without non-locality? [duplicate]
There are many different interpretations of quantum mechanics. Some posit determinism and non-local influences between particles. Others do not, such as in the Copenhagen interpretation.
My question ...
user401242
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Could reducing entanglement by unitary operations allow for FTL-communication? (and why not?)
About the closure: This Question is about why manipulating 1 particle of an entangled pair unitarily can’t cause measurable consequences on the other and how this manifests in the concretely described ...
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Can a non-local theory be consistent with special relativity?
If there was a non-local theory that explained quantum entanglement correlations, does it follow that it would violate special relativity?
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All the logically possible ways to get around Bell-type inequalities
I'm a high school student, so my (mis)understanding here is not very rigorous or precise, but I will write it below so as to concretely frame my question:
Bell's theorem takes three assumptions ...
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Do Bell’s inequalities assume determinism?
I was watching a video of Tim Maudlin where he talks about how the CHSH version of Bell’s inequalities do not assume determinism and only assume locality. He said that it is a common misconception ...
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Why do particles need a signal to travel to another to affect it? [closed]
I was reading up on quantum entanglement, non locality, and how people interpret QM to still be local in the sense that it does not allow for faster than light communication signals.
I have two ...
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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
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Does local realism imply entangled photons are equal (or opposite)?
I'm watching a video about Bell's inequality and how there can be no local hidden variables. They explain it using photons and whether they pass through a polarizer or not when they're oriented at ...
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What was the fallacy in EPRs chain of arguments?
Let's say, there is an entangled system of two electrons with opposite spins; The joint system is in a state of eigenvectors for z-Spin ( $S_z$) with both particles far away from each other:
$$|\Psi\...
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Learning contextual data using a variational quantum circuit
This question is about contextuality in quantum mechanics, about non-quantum data also showing contextuality.
Definition for the specifics of the question as well as an example of contextuality in ...
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What is the consensus among physicists on whether quantum mechanics has non-locality? [closed]
According to this article here by the SEP,
Following Bell's work, a broad consensus has it that the quantum realm involves some type of non-locality (for examples, see Clauser and Horne 1974, Jarrett ...
user385269
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What does non-local transport mean in plasmas physics?
I found a lot of plasma physics works that talks about non-local transport, what is non-local transport in plasmas? What does non-local transport mean ? Some examples please.
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Newton's second law - local laws and non-local laws
What are local laws? I was reading this line in a book...
Newtons second law is a local law. This means that it applies to a particle at a particular instant without taking into consideration any ...
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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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Contradiction of propagation speed of gravitational waves with non-locality of gravity?
Although LIGO at 2016 verified the speed of a traverse gravitational wave being the speed of light in a vacuum $c$ there is also the fact that gravity is a non-local phenomenon, meaning that it is not ...
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Justification for the derivative expansion in the Exact Renormalization Group
In the Exact Renormalization Group formalism, specifically the formalism of Wetterich, one writes down an evolution equation for the effective average action $\Gamma_k[\varphi]$, see f.ex
$$
\...
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Difference between local and non-local optical model potential?
As far as I understand, local OMP (optical model potential) depends only on the relative position, and non-local OMP depends on relative position and momentum.
I am searching for more information so ...
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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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Is the possible Bell's test loophole of entangled particles communicating at a non instantaneous but FTL speed addressed and eliminated? [closed]
TLDR:
There seems to be a loophole in Bell's test that is not addressed or eliminated before we can successfully conclude that it proves that the Universe is unreal and non local. The entangled ...
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How can we be sure Bell's theorem disproves local realism when we are not sure whether the measuring apparatus is in some form of entanglement or not? [duplicate]
Bell's therorem seems to disprove localism because measuring, let's say spin of an entangled electron, seem to communicate the measurement to it's another pair instantaneously.
But isn't another thing ...
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Are field theories where free energy density depends on 2nd-order derivative non-local?
It is accepted that infinite order of derivatives in field theory lead to non-local effects while finite number of them local.
reference within physics stack exchange
Let’s take a lattice with next-...
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Is there any limit to the utility of quantum measurements in the sense of a Lieb-Robinson bound?
So the Lieb-Robinson bound of 1972 derives an emergent maximum speed $v \ll c$ of the propagation of quantum information under time evolution generated by some local Hamiltonian $H(t)$. Basically, ...
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Does non-local hidden variable theory predict the outcome of an experiment? [duplicate]
I am trying to understand what decides the outcome of an experiment and if there is any theory (e.g. non-local hidden variable theory) that is able to predict the outcome.
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Quantum Entanglement: Is Non-locality Inherent or Does It Violate Causality? [duplicate]
Dear Physics Stack Exchange community,
I am intrigued by the concept of quantum entanglement and its implications for our understanding of the fundamental nature of reality. I have come across various ...
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Why does it make sense to add/subtract the results of measuring in 2 different bases in Bell's inequality when each observer only measures 1 property?
In the CHSH inequality, we construct an experiment whereby two observers each receive a particle and measure two given properties of their particles, for which the outcomes are ±1. We then consider ...
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