Questions tagged [locality]
The locality tag has no usage guidance.
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Is Quantum randomness true randomness? [closed]
I would like you guys to read it, and see whether it makes sense, and correct me if anything is wrong.
I'm not an expert on these topics, so I understand if very wrong. It would be wonderful if you ...
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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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Well-definedness of commutation relation in commuting local Hamiltonians
I'm reading the famous paper by Haah: Local stabilizer codes in three dimensions without string logical operators. In the last sentence of the introduction, he wrote:
A logical operator is a Pauli ...
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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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Are field theories necessary to make accurate predictions or do they just make calculations easier?
For example, if we really wanted to, could we, at least in principle, model electromagnetism just considering interactions between charged particles without using the EM field? That is, is it ...
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Understanding superdeterminism
I was reading about superdeterminism and it was a bit counter-intuitive. The idea of having a hidden variable on the measurement device is very rational. For example, if we emit light to a constrained ...
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Is a super-deterministic universe local or nonlocal? [closed]
Bell predicted predetermined (nonlocal) choice as the criteria for a super-deterministic universe.
...our belief that we are free to choose to do one experiment rather
than another, absolutely ...
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Understanding this abstract Lagrangian of effective field theory
I'm learning Wilson's approach to renormalization and the Effective Field Theory. Typically, the theory is defined by a Lagrangian valid up to some scale $Λ$. I saw these two definitions for 4-...
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Ostrogradsky instability and fractional derivatives
Are fractional derivatives (or even more generally differentegrals) also under the scope of the Ostrogradsky instability theorem?
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How does Bell's theorem disprove realism?
I am told that the the violation of Bell's inequalities prove that the universe cannot have local realism. That is to say, the universe cannot both be local and real.
I understand how Bell's theorem ...
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What does it mean to say the universe is not locally real? [duplicate]
Pardon me if this is a naive question.
What is difference between saying space-time is not locally real, and saying it is not real?
The proposal that the universe is not locally real seems to imply ...
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How is the non-locality of a theory apparent from its mathematical form?
I am reading Relativistic Quantum Mechanics by Bjorken and Drell and on page 5 they present the following attempt at a relativistic Hamiltonian for a free particle
\begin{equation}
i\hbar\frac{\...
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How localized are photons in a quantum field?
Are photons or other quanta at least somewhat localized in a quantum field?
My limited understanding of quantum field theory is that photons or other fundamental particles (quanta) are excitations of ...
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Non- Local operators and Entanglement
Given a separable state, $|\psi\rangle$ = $|a\rangle\otimes|b\rangle$, operating on this state with a local operator of the form, $A\otimes B$ will not lead to an entangled state. Is the converse true?...
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