Establishing consistency between a wave model of the photon and a particle model

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Discussion Overview

The discussion revolves around the relationship between wave and particle models of photons, specifically examining the consistency of these models within the framework of quantum electrodynamics (QED) and quantum mechanics (QM). Participants explore the implications of treating the electromagnetic field of a single photon and the energy calculations associated with multiple photons.

Discussion Character

  • Debate/contested
  • Exploratory
  • Technical explanation

Main Points Raised

  • One participant notes that the intensity of an electromagnetic wave is proportional to the square of the electric field amplitude, while the energy of N photons is given by the product of the number of photons and the energy of a single photon, raising questions about the consistency of these models.
  • Another participant challenges the validity of considering the electromagnetic field of a single photon, questioning the usefulness of treating a quantum system not in an eigenstate of electric field as if it were.
  • A comparison is made to the Bohr model of the atom, suggesting that assuming circular electron orbits, while not entirely correct, can still yield useful results for energy computations.
  • Some participants express skepticism about the proposed model's consistency with QED and QM, suggesting it resembles a personal theory rather than an established framework.
  • A later reply references a paper on Quantum Phase Operators, indicating that there are still unresolved questions regarding the phase of the photon wave function, particularly for small numbers of photons.

Areas of Agreement / Disagreement

Participants express disagreement regarding the validity of the proposed model's consistency with established theories like QED and QM. There is no consensus on the acceptability of the model, with some viewing it as a personal theory lacking support from established physics.

Contextual Notes

Participants note limitations in the current understanding of the phase of the photon wave function, particularly for small numbers of photons, and the challenges in reconciling wave and particle descriptions within quantum mechanics.

Charles Link
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Note: added to the title should be "and a particle description". ## \\ ## The intensity (energy density) of an electromagnetic wave is proportional to the second power of the electric field amplitude, i.e. intensity ## I=n \, E^2 ##, apart from proportionality constants. Meanwhile the energy contained in N photons is ## U=N \, E_p ##, where ## E_p=\hbar \omega ## is the energy of a single photon. It may be a poor physics to consider the electomagnetic field ## E_i ## of a single photon, but assuming we can, the superposition of ## N ## photons in the same mode all in phase with each other results in a state that has ## N^2 ## that of the initial energy, since ## E_{total}=NE_i ## in that case. One explanation that avoids this dilemma is to have the phases of each of the individual photons to be random when all of the photons are in the same photon mode, so that the phasor diagram to compute the resultant ## E_{total} ## is that of a 2-D random walk. For large ## N ##, ## E_{total} ## will be proportional to ## \sqrt{N } ## and the energy will be proportional to ## N ##, (i.e. ## E_{total} \approx \sqrt{N} E_i ##), as it needs to be. The question I have is if this explanation is consistent with the presently accepted way of how the photon is modeled, by QED for example?
 
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Charles Link said:
It may be a poor physics to consider the electomagnetic field Ei E_i of a single photon

Then why are you doing it?

You are taking a quantum mechanical system that is not in an eigenstate of electric field and treating it as if it were. Why should that produce anything helpful?
 
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Vanadium 50 said:
Then why are you doing it?

You are taking a quantum mechanical system that is not in an eigenstate of electric field and treating it as if it were. Why should that produce anything helpful?
In some ways, it may be like doing what Bohr did by assuming circular electron orbits in the Bohr model of the atom. Letting ## E_i(t)=E_i cos(\omega t +\phi) ## for some random but constant ## \phi ## does give a result that gives consistency (for energy computations) to the classical model of the electromagnetic field. ## \\ ## Additional comment: The Bohr model may not be completely correct, but it is still the quickest way to compute the wavelengths of the principal transitions in the hydrogen atom.
 
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This sounds a lot like a personal theory.

Anyway, you have your answer. No, this is not something consistent with QED because it's not even consistent with QM.
 
Vanadium 50 said:
This sounds a lot like a personal theory.

Anyway, you have your answer. No, this is not something consistent with QED because it's not even consistent with QM.
Thank you for the input. It probably does then fall into the category of a personal theory. Unless anyone else has anything that keeps it from being that, it appears under the Physics Forum rules, further discussion would not be favored and/or not allowed, which is really ok with me. :) :)
 
Charles Link said:
Note: added to the title should be "and a particle description".
Done.
(and in the future if you need a correction of this sort, just report your own post - that brings it to the attention of the mentors so that one of us can fix it for you).
 
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One additional comment: I just did a quick google of the subject of Quantum Phase Operators and the following paper showed up: Quantum Phase and Quantum Phase Operators, Some Physics and Some History by Michael Martin Nieto dated 1993 I believe. Here is a "link" : http://cds.cern.ch/record/567453/files/9304036.pdf Some of the mathematics and some of the conclusions are above my present level, but I found it of much interest. At the time of the writing of the paper, it appears there is still no good answer for what the phase of the photon wave function might be for small ## N ##.
 

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