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I read the article and have some questions.
Thanks. chgenly — Preceding unsigned comment added by Chgenly ( talk • contribs) 20:13, 17 November 2013 (UTC)
In the second section "Electromagnetic field and vectorpotential" it is stated in the expansion of the vectorpotential A into Fourier-components, that "[...] runs over one side, positive or negative. (The component of Fourier basis is complex conjugate of component of as is real.)"
In section 7 "Photon Momentum" however it is said that "The term could be dropped, because when one sums over the allowed , cancels with ." If I see it correctly, one also needs "both sides" of -space, in order to derive the second formula in this section from the first in this section.
So how do these two statements relate? Is it my misunderstanding? What is the error here?
After further thoughts and computations it seems to me, that the first quoted sentence is conceptually wrong here. Can you really talk about the "reality" of a quantum physical "field"? If I take the full -space into the sum for my vector-potential, neglect the "" in the square roots in the conversion from the classic amplitudes to the operators and symmetrically quantize the absolute values in the expression for the energy-Hamiltonian, then I can obtain the same result, as stated in the original article. But also I can show the expression for the momentum [using ; here the minus originates from the choice of the "phase" in front of the basis vectors for the circular polarization].
I didn't notice any mention that QED is still not mathematically well-defined! David edwards ( talk) 12:00, 1 April 2018 (UTC)David edwards
It's written in the opening the the z-component of the spin is either -1 or +1, but afaik it can also be 0.. is that a mistake? נועם ימיני ( talk) 20:57, 3 May 2020 (UTC)
Many seem to think the classical electromagnetic field and electromagnetic radiation are the same thing. This of course is completely false attraction per coulombs law is part of the classical electromagnetic field there is no need for photons for real attraction between moving charges to occur. Only electromagnetic radiation has been shown to be quantized. Bill field pulse ( talk) 17:07, 18 January 2024 (UTC)
Quondum says "stick to the literature" and he does not see that there is a type of EM field when no radiation is present. He does not feel we have a role doing better than the literature. If ancient literature confused the two that is what we are stuck with. If a modern writer never learned the difference we are stuck with it. If we are trampled by dwarfs we do not see very far. Bill field pulse ( talk) 20:46, 21 January 2024 (UTC)
Since the near field has electric field peaks and magnetic field peaks which are out of phase they cannot be produced by any combination of photons which have the peaks in phase at all times. We need to clarify that only the far field is quantized in this way. Bill field pulse ( talk) 19:50, 1 April 2024 (UTC)
![]() | This article is rated C-class on Wikipedia's
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I read the article and have some questions.
Thanks. chgenly — Preceding unsigned comment added by Chgenly ( talk • contribs) 20:13, 17 November 2013 (UTC)
In the second section "Electromagnetic field and vectorpotential" it is stated in the expansion of the vectorpotential A into Fourier-components, that "[...] runs over one side, positive or negative. (The component of Fourier basis is complex conjugate of component of as is real.)"
In section 7 "Photon Momentum" however it is said that "The term could be dropped, because when one sums over the allowed , cancels with ." If I see it correctly, one also needs "both sides" of -space, in order to derive the second formula in this section from the first in this section.
So how do these two statements relate? Is it my misunderstanding? What is the error here?
After further thoughts and computations it seems to me, that the first quoted sentence is conceptually wrong here. Can you really talk about the "reality" of a quantum physical "field"? If I take the full -space into the sum for my vector-potential, neglect the "" in the square roots in the conversion from the classic amplitudes to the operators and symmetrically quantize the absolute values in the expression for the energy-Hamiltonian, then I can obtain the same result, as stated in the original article. But also I can show the expression for the momentum [using ; here the minus originates from the choice of the "phase" in front of the basis vectors for the circular polarization].
I didn't notice any mention that QED is still not mathematically well-defined! David edwards ( talk) 12:00, 1 April 2018 (UTC)David edwards
It's written in the opening the the z-component of the spin is either -1 or +1, but afaik it can also be 0.. is that a mistake? נועם ימיני ( talk) 20:57, 3 May 2020 (UTC)
Many seem to think the classical electromagnetic field and electromagnetic radiation are the same thing. This of course is completely false attraction per coulombs law is part of the classical electromagnetic field there is no need for photons for real attraction between moving charges to occur. Only electromagnetic radiation has been shown to be quantized. Bill field pulse ( talk) 17:07, 18 January 2024 (UTC)
Quondum says "stick to the literature" and he does not see that there is a type of EM field when no radiation is present. He does not feel we have a role doing better than the literature. If ancient literature confused the two that is what we are stuck with. If a modern writer never learned the difference we are stuck with it. If we are trampled by dwarfs we do not see very far. Bill field pulse ( talk) 20:46, 21 January 2024 (UTC)
Since the near field has electric field peaks and magnetic field peaks which are out of phase they cannot be produced by any combination of photons which have the peaks in phase at all times. We need to clarify that only the far field is quantized in this way. Bill field pulse ( talk) 19:50, 1 April 2024 (UTC)