Dear Ilian,

The "photons" referred to as "quantum excitations of the field" are in reality a mathematical concept whose real name is "virtual photons" that belong to the Quantum Field theory, and can be used with the QED method defined by Feynman to calculate the levels of energy and force involved at any distance between a pair of charged particles. They amount to a quantization of the infinitesimally progressive Coulomb force interaction that emerges from Maxwell's first equation, that is, Gauss's equation for the electric field.

In this context, they amount to locally stationary states between charges that do not really move in space.

The failure in many reference books and papers to clearly identify them as "virtual photons" as Feynman recommended is the source of much confusion in the community.

The "real electromagnetic photons" are made of only energy and it is them that move at the speed of light c.

Ok I see. Stationary charges=virtual photons.(Though how would they be EM in a stationary reference frame? There is just electric field.)

But is the EM field (underlying in all space) not excited when a charge is moving and a real photon emerges. Is this not described in QFT as an excitation of the EM field?

Or the quantization in an atom where the electron is rotating around the nucleus? Here the charge is definately moving and the photons must be real?

Dear Ilian,

You are right about "just the electric field" when QED "virtual photons" are considered. It would be more Stationary Coulomb-force/corresponding-energy=virtual-photon at this location between two charges, whether the charges are moving or not relative to each other.

In the underlying QFT theory. the whole universe is deemed filled with an underlying neutral energy quantum vacuum field where particle-antiparticle pairs are spontaneously created by means of assumed spontaneous natural quantum vacuum fluctuations.

I am no specialist of QFT, but that's the general idea.

We must think that all has not yet be explained regarding electromagnetism.

In physical reality we know that real electromagnetic photons are emitted in nature only when electrons are captured by atoms, or jump from a metastable orbital to a closer orbital after having absorbed an incoming electromagnetic photon that caused them to jump further out, evacuating the energy they accumulated as they accelerated to get there. That's why we can see about ourselves with the visible frequencies range. We are hit by the outgoing EM photons thus emitted. There are also emission involving nuclei.

It is not that obvious that electrons would be moving on orbits about atomic nuclei as you suggest. From the quantum mechanics perspective, the one thing that is established is that they are located within a volume about nuclei within which we know that they are located, without being able to determine currently whether they remain localized within this volume as could be represented with classical mechanics (the Bohr atom) or whether their energy is spread out, according to a statistical distribution pattern that can be established with Heisenberg's method.

As for the charge in relation with the wave function, there are issues here, since the charge is related to electromagnetism, which is not completely in sync with Quantum Mechanics, although QFT is in sync with Maxwell's electromagnetic theory.

Dear Andre,

you say 'incoming photon'. This picture of a moving object is in fact this what I can not grasp in reference to 'exitation of the field'. In this view it seems like there is nothing moving but the field wrinkles with the mode everywhere in whole universe and maybe beyound, which is OK when speaking about virtual photons. Surely there are moving photons and I can see how are they wrinkles of the field.

By the way I found a review from A.Neumeyer about these isue. But I need time to understand it. If you like I will send it to you. Just let me know.

Best regards.

Dear Ilian,

Yes, I am interested in reading this review from A. Neumeyer. Please give me the link.

When I speak of an "incoming photon", i speak of course of a real electromagnetic photon, not of the virtual photons of QFT or QED. This relates to the confusion caused by the fact that many authors neglect to add the word "virtual" when referring to the QFT or QED virtual photons.

The real photons are those that Einstein and Planck were taking about and whose existence was proven by the photoelectric effect. They are those that enter our eyes and strike the cells of our retinas and cause us to see our surroundings.

Maxwell made the hypothesis that electromagnetic energy propagates as waves in vacuum, but Walter Wien discovered that light interacted in a discontinuous manner with matter, and then Planck established the equation that allows calculating the energy of these individual "energy quanta". Einstein then conceived of the photoelectric experiment to measure their energy. These quanta were later named "photons".

It was then understood that electromagnetic energy does not propagate as electromagnetic waves in vacuum as Maxwell had supposed, but as separate individual electromagnetic photons at the submicroscopic level. Maxwell's wave theory is ok when applied at the macroscopic level, but at the submicroscopic level, we now understand that what we perceive as a wave behavior is due to the presence of innumerable localized EM photons whose global behavior can be mathematically dealt with as if it was a continuous wave phenomenon.

Louis de Broglie established in the 1930's the hypothesis of how the electromagnetic energy could be internally structured to sustain such self-sustaining localized moving electromagnetic photons and this inner structure was recently clarified according to his theory:

https://www.omicsonline.org/open-access/on-de-broglies-doubleparticle-photon-hypothesis-2090-0902-1000153.pdf

The virtual photons of QFT and QED only represent in a quantized way the Coulomb force interaction between charged particles.

This is put in perspective in this other paper in section "Continuity vs. discontinuity with respect to…" starting on page 2 of this paper:

https://www.omicsonline.org/open-access/on-adiabatic-processes-at-the-elementary-particle-level-2090-0902-1000177.pdf

Hope this helps you to clarify the difference between virtual photons and real electromagnetic photons.

Best Regards

André

As it stands, the assertion "photons are quantum excitations of the field" is too glib. There are implicit assumptions made that need to be identified and understood. Photons are empirically identifiable only with signals in apparatus whilst quantum fields are convenient theoretical constructs. To believe otherwise is to allow classical modes of thinking to assume undue importance in quantum physics.

Just like any quantum field, through creation and annihilation operators, that define the number operator. This is presented in all textbooks on field theory.

It doesn't have anything to do with solitons.

Let us consider the procedure of e-m field quantization.

1) We decompose e-m field in box by Fourier series. I.e. we decompose it into standing wave.

2) Each oscillation mode, i.e. each standing wave is considered as harmonic oscillator. (It is linear! No solitons!)

3) Each harmonic oscillator is quantized.

4) Photon is a portion of energy \hbar\omega, which move an oscillator one energy level up.

So, photon correspond to some standing wave, which delocalized along the whole box.

Stoil Ganchev Donev

Dear Ilian!

My view on the "photon notion" can be found in the added "pdf-" file. For a more detailed view - my book: "Geometric view on photon-like object", arXiv: 12108323. SGD.pdf · 174.62 KB

Dear Stoil,

You produced quite an interesting document.

Maybe would you be interested in this one which tackles the same issues from an entirely different angle:

https://www.omicsonline.org/open-access/gravitation-quantum-mechanics-and-the-least-action-electromagneticequilibrium-states-2329-6542-1000152.pdf

Dear Mikhail,

yes I know this. Just a question about p.2: how do you understand one oscillator to the each mode? For me there is one oscillator for each point for each wave! So for each mode there is an accountable amount of oscillators all with same frequency and with a phase leg.

Also: what photons are doing there after this mathematical trick from a physicists point of view? They seam to have their energy spread over all volume and if registered to have energy in just one point? Also: are this real photons or virtual? I think there must be real. But then how to introduce them in the box? With a source you cannot change the energy everywhere! Also why on earth should the energy be greatest in the center for I mode?

Dear Andre!

Thank you for sending me your paper. I'm going to read it these days, and will be thankful to discuss with you the basics of electrodynamics and gravitation theories.

Looking forward!

Bye for now!

Illian, the Fourier transform is a change of basis in the space of functions. So a harmonic oscillator at one point and a mode are essentially the same. The big difference is that at each point the harmonic oscillator is coupled to its neighbours, while a mode is independent.

A photon is as delocalised as any quantum particle. The wave function represent the probability amplitude of detecting the particle at a given point. In the case of a plane wave, the probability is the same anywhere, that's the case of a photon with a well defined energy. But in quantum mechanics, any linear superposition of the basis states is allowed. Then a physical photon is usually in a state more or less localised, that is, a wave packet. It is characterised by it coherence length, which is roughly the uncertainty on its position.

Dear Ilian,

This "mathematical trick" is just search of eigen oscillations.

One could consider a solid body, instead of box with e-m field. To find the eigen oscillation of solid body is a standard mechanical problem. The only difference is quantization (pp 3,4). For solid body instead of photons one finds phonons.

One could consider one oscillator in each point of media, but these oscillators interact with neighbors. Oscillators, which correspond to eigen oscillations are independent. (It is still classical mechanics!)

Dear Mikhail, I don't think that if you look at each point as oscillator, there are coupled. There all are moving with the same frequency and just the amplitude is different (especially the first mode). Zero at the walls and max in the middle. I read that the standing waves and the oscillator are regarded the same because they have the same Hamiltonian H. H specifies the dynamics of the wavefunction. But for oscillator one has only one argument x, where for the standing wave one has two arguments in the wavefunction x, y?

It is very good that you wrote about the solid body and phonons. Now I have clearer view. If you want make a phonon - a standing wave -you have a disturbance traveling from a point to the walls - so transient processes and just then a standing wave. But for quantization of EM field transient processes are not regarded. The wave appears at once in the whole volume. Which is strange for me.

Dear Claude-Pierre,

I suppose that you say that if we have a EM soliton in a box, we can see it as oscillators on the lenght of the box, and also as sum (integral) of standing waves with some coefficients (e.g. Fourier decomposition).

This is what Debye made with the black body radiation in a box.

Now you say that this are the photons and they are not localized but spread the entire box every instant.

Mathematically this is of course OK. But physically we have a very localized moving object travelling from side to side and now we substitute it with many unlocalized modes and call them photons! This can not be reality in nature nevertheless it is convenient for analysis.

Dear Ilian,

Transient processes are not considered for quantum transitions. Photons creation or phonon it does not matter.

Quantum theory is a theory of metamorphosis. Each quantum process is metamorphosis of initial state to final state. Even if initial and final states are the same, the process is considered as a sort of metamorphosis.

If one consider field in each point as oscillator, these oscillators have to be coupled, because one CAN NOT initiate independent oscillations of each oscillator. If one consider each standing wave as oscillator, these oscillators ARE independent.

Ok surely the transient processes are not regarded in QM. (that is exactly what I am saying). But are they absent in reality?

If if an atom in the wall emits a quantum of energy at time 0 it is near the atom, whereas the mode is in the whole volume. The same with phonons. It is in harsh conflict with relativity while you can register the photon everywhere in the box, the speed is greater than c.

If an atom in the wall emits a quantum of energy in the visible range (an electromagnetic photon) at time 0, and if it hits one cell in your retina at time 0+dt, then it seems to me that there is no way that it could have been anywhere during its transit but on a clearly definable trajectory that it had to follow from this atom to your eye at velocity c.

From the knowledge base that we have, from its observed color, its frequency and thus its energy can be measured, leading to identifying which type of atom from the periodic table had one electron jump closer to its nucleus to emit this amount of energy.

There seems to be no way either that it would not have been localized all along the way after having been emitted from such a point-like localized area, otherwise how could it still have had all of its emitted energy on reception in such a practically point-like localized area.

Andre,

This is why you need to look at Vision-Space! There is something else going on and its not related to intensity and our current notions about measurement. The retina is performing two types of computation and if scientists want to understand these issues a good place to start is by understanding what's required in us being objective. ie. the data structures involved in the phenomenon of vision. We have to infer from these manifestations. What we make of the interaction with EMR is (un surprisingly) prior-to and in advance of our current conceptual understanding of the situation.

Ilian and Mikhail I think you would be interested as well. The principle data formation we generate is a field structure the provides us with proximity cues. We can model this data-structure in Vision-Space but we can't explain how it gets there. This can't be related to fundamental optics. We as complex bio systems have to be taking something else from the light array. Something that our current instrumentation has not been designed to interface with.

Dear John,

As I think I mentioned previously to you, what you call Vision-Space is in reality what our "awareness" observes at the output layer of the neocortex, which are the remembered correlations automatically drawn by the neural network from the continuous input of countless bits of sensory data that come to the entry layer of the neocortex after having been picked up by our nerve endings, including what our retinae perceive.

This was understood in depth long ago at the "hardware" level by Donald Hebb in the 1940's, from which were eventually developed artificial neural networks, and simulated programmed neural net applications now being developed in the AI community.

At the functional level, the working of the neocortex was explored and understood by Pavlov, Korzybski and Chauchard.

Their results are available, but unfortunately not yet translated into a common language.

Hebb and Korzybski in English, Pavlov in German and Russian and Chauchard in French.