[pensador (OP)]

I started to read the paper you linked flummoxed. Got stuck on "  At any instant moment its energy, momentum and spin angular momentum keep conservation. Its wavelike property originates from the periodicity of its helically rotating motion, instead of its wave spreading all over the place "

What do they mean by spin here? If you translated a electrons spin into classical spin it would spin faster than light speed in a vacuum?

The spin of the photon is related in the model to its angular momentum through the vector e which acts for a photon as the spin part of the wave function. They equate this to +1 or -1. At least this is how I read it. Nowhere is FTL indicated the limiting speed is c. The interesting thing about this model is that they appear to have a model of a single photon, that is based on Maxwells equations. Which I thought might be of interest to AlanCalverd. You may note they also mention the double slit experiment, and bohms theory as well as other photon theories to explain the double slit experiment.

I think I have a pretty plausible visual image of a photon now. I am still looking for the 2 virtual particle representation of a photon I stumbled across some time ago.  If I find it I will post it for completeness.   

[yor_on]

Yes, that's the only way I make sense of the paper. But it's also a fact that the spin of a electron is 'FTL' if you translate it into a classical 'speed'. So either the 'spin' they discuss for a photon, which it has, is uncoupled to the spin of a electron, or it isn't? In the first case we now have two definitions of what 'spin' means. One quantum mechanical in where 'spin' has no classical counterpart as shown by the electron, the other classical. The classical demands splitting 'spin' into two categories, one classical (photon) and the other strictly quantum mechanical (electron FTL).

[pensador (OP)]

Yes, that's the only way I make sense of the paper. But it's also a fact that the spin of a electron is 'FTL' if you translate it into a classical 'speed'. So either the 'spin' they discuss for a photon, which it has, is uncoupled to the spin of a electron, or it isn't? In the first case we now have two definitions of what 'spin' means. One quantum mechanical in where 'spin' has no classical counterpart as shown by the electron, the other classical. The classical demands splitting 'spin' into two categories, one classical (photon) and the other strictly quantum mechanical (electron FTL).

You have me a little confused
 
Electrons are not involved in the pdf mentioned above. But yes lots of models of electrons exist also as spinning particles donuts and electron fogs/fields etc.

Are you perhaps relating to the pair of virtual particles representing a photon which I mentioned? I still havent found the link. The spins of the two massless virtual particles added up to 1.   

Nothing is FTL unless perhaps, information transfer via entanglement depending on your point of view, or maybe the expansion and contraction of space.

The spin of an electron must therefore must be <= light speed, which might indicate the model you are thinking of needs a smaller radius, or something is not right.   

An electron not connected to an nucleus in a orbital shell, does not give off photons, unless it is like a muon, which rapidly decays to an electron and a photon. Is this what you are getting at ?

When an electron loses energy in an atom it changes orbitals, releasing energy in the form of inertia which is locked inside a photon. The photon carries away the energy until it is reabsorbed. 

As I said You have me a little confused you will have to explain what you are getting at ??

[pensador (OP)]

No, not an electric field, but a selfpropagating electromagnetic wave as described by Maxwell.

A photon IS a quantum fluctuation in space, that MIGHT be surrounded by a pilot wave as explained in Bohm and de Broglie pilot wave theory.https://en.wikipedia.org/wiki/Pilot_wave_theory   

I have manged to convince myself that photons and virtual photons as used in QED are one and the same, they are not hypothetical. A virtual photon transfers a force as required by the virtual photon from A to B. A photon transfers a force from A to B. https://en.wikipedia.org/wiki/Quantum_electrodynamics#Basic_constructions

Feynman I think nails it, its a quantum representation of maxwells ideas
"
The key components of Feynman's presentation of QED are three basic actions.[1]:85
A photon goes from one place and time to another place and time.
An electron goes from one place and time to another place and time.
An electron emits or absorbs a photon at a certain place and time.
"

How are forces transferred from A to B at the quantum level? it is by photons. A photon has inertia, Einstein says so so the inertia is transferred or absorbed by photons when electrons change orbit.

Do Virtual photons work in the same way, certainly virtual particles have energy and momentum according to feynman. In the HUP virtual particles appear as pairs temporarily borrowing energy from the vacuum of space, they also exhibit momentum as shown in the Casimir effect, and can be converted to real particles as shown in the dynamic casimir effect.

If an electron emits a photon or transfers its energy to a virtual photon, it is electrically neutral and has no magentic field, it has spin and polarization. To achieve this using a virtual particles a pair is required with correct spin and charge to give spin 1. and I cant still cant find the link I am looking for 

[alancalverd]

Photons are generated by electrons changing energy levels in atoms.

Or by free electrons decelerating in a target, or accelerating in a wiggler. Same principle as radio waves, just higher energies. And of course some nuclei emit photons with no electron involvement at all. 

Fascinating stuff, physics.

[pensador (OP)]

Photons are generated by electrons changing energy levels in atoms.

Or by free electrons decelerating in a target, or accelerating in a wiggler. Same principle as radio waves, just higher energies. And of course some nuclei emit photons with no electron involvement at all. 

Fascinating stuff, physics.

Yes radio waves will induce electrons to move, via electro magnetic induction. A solitary electron decelerating as it hits a target is not the same as a radio wave, which has different properties. I dont think radio waves can make a TV screen glow, the same way an electron beam can, or even reproduce a double slit experiment results in the same way a particle can. Radio waves can heat stuff up in a microwave.

Ref nuclei its down to stability and flavour. There are many ways of brewing up reactions that make things glow Nuclear reactions are explained by quantum mechanics not maxwells equations as are photons. Q.E.D     

I agree 100%. It is Fascinating. Whilst being aware of QED I never really paid it much attention before.

[yor_on]

I don't know flummoxed, it's just logic. Either you have electrons spin doing FTL, which can be checked. Or they don't?

what a photon and a electron have in common is this idea of a 'spin'.  In the case of a 'photon' if you want it to be classical, its 'spin' needs to be covered by relativity. Which then bring it down under 'c'. In the case of a electron it was confirmed somewhere in the thirties that if you wanted to translate it into a 'classical spin' (as in a carousel)  its 'speed' would be FTL.

That's where I got stuck
 

[pensador (OP)]

I don't know flummoxed, it's just logic. Either you have electrons spin doing FTL, which can be checked. Or they don't?

what a photon and a electron have in common is this idea of a 'spin'.  In the case of a 'photon' if you want it to be classical, its 'spin' needs to be covered by relativity. Which then bring it down under 'c'. In the case of a electron it was confirmed somewhere in the thirties that if you wanted to translate it into a 'classical spin' (as in a carousel)  its 'speed' would be FTL.

That's where I got stuck

Have you not answered your own question FTL is not possible therefore the classical interpretation is not quite correct. 

[alancalverd]

Sorry, flummoxed, but you seem to be ploughing a lonely furrow to nowhere. If you can't accept the basic fact that accelerating electrons generate photons, you won't harvest any physics or understand why we abondoned orbits and invented quantum mechanics.

Good luck in your quest, and farewell.

[pensador (OP)]

If you can't accept the basic fact that accelerating electrons generate photons, you won't harvest any physics or understand why we abondoned orbits and invented quantum mechanics.

Good luck in your quest, and farewell.

I have never disputed electrons can generate photons. That is a strawman argument typical of southerners
Enjoy your warm lager and fixed speed of c in your Maxwells equations   So you have switched to Quantum theory now excellent. 

Farewell.

[yor_on]

Let us put it this way.
I don't know flummoxed?

They need a argument for how to treat other particles spin.
If they find it it will be interesting.

Myself I lean to the quantum mechanical approach.
Which shouldn't be read as I 'know'

[yor_on]

And Flummoxed
The point of physics is not in relations, it's in the logic you apply to a problem.
And what you can learn

That's what makes a theory
Don't let relations scare you away

[Colin2B]

Haven’t had time to respond to this thread as been busy and lots of spam etc hitting, but have made a few notes along the way, some may overlap with @alancalverd

Photons have spin 1, am I correct in thinking the spin of a photon is related to its angular momentum, and wave shape? ie polarization.

Spin 1, helicity h two components of classical RH & LH circular polarisation.

Is it possible a photon consists of 2 virtual particles with opposite charges, spinning around each other? 

My photon picture at the moment is a virtual particle pair inside a pilot wave from bohemian theory. Is this plausible ?

Not unless you are proposing a new theory ;-)

There are many problems with the Bohmian theory.
Eg, as @PmbPhy  points out “Note that the Schrodinger equation only holds for non-relativistic particles and photons are relativistic particles. “
But, it is not necessary to postulate the existence of a pilot wave. Take the double slit experiment and consider that one photon doth not a diffraction pattern make; we need more than one to build the pattern. Once you have more than one there is a finite probability that a photon will pass through one of the slits, and we can assume equal probability for each slit. Clearly, when the photon hits the screen, being a wave, its phase is determined by the distance between slit and screen (as in the classical wave model) and the relative phase of 2 photons will determine the superposition effect. However, when modelling a single photon we still have to say that it passed through both slits in order to apply the probabilistic and superposition models.

A photon can be visualised as a quantum of the em/photon field, propagating with the oscillating E and B field vectors rotating around the z axis (direction of travel) such that the vectors describe a helical wave in spacetime.

The big difference between a virtual photons and real photons is life time.

No. Unlike photons, virtual photons do not have a relationship between ω and k, nor between energy and momentum. They don’t propagate and can appear in the context of a direct interaction between charged particles, while real photons are the electromagnetic waves send out.
Reread Strassler on the subject, he is very clear.

Photons are generated by electrons changing energy levels in atoms.

That’s not the only way, they are also generated by “radio waves are generated by electicity in radio masts, and satellite dishes etc”.
A photon is a quantisation of the em wave and radio waves also have them, we just don’t use them in ordinary radio as they have very low energy so quantum effects don’t become apparent and classical wave theory works fine.

wave particle duality whereby a wave collapses to become a particle.

The wave does not collapse to become a particle. There are situations where an interaction, eg when the photon gives up its energy to an atom, which can be modelled as a particle interaction. Don’t make the mistake of thinking that these models represent some ‘reality’. 

Photons maintain there strength regardless of distance travelled. Radio waves do not, they get weaker.

This is a total red herring due to a misunderstanding about the difference between individual photons and the en-mass effect of billions of photons. Photons leaving a point source (by the billions in all directions) disperse and result in a reduction in intensity following the inverse sq law in just the same way as the wave model.
A plane em wave, eg from a distant star, does not get weaker with distance and some of the maths used to model a photon show it as a group of plane waves.

I dont think radio waves can make a TV screen glow, the same way an electron beam can, or even reproduce a double slit experiment results in the same way a particle can.

You have obviously never worked with high power radio transmitters. I can assure you that nearby tv screens will glow, and it is possible to do the double slit experiment with radio waves - I did myself and it is a standard undergraduate experiment eg https://www.haystack.mit.edu/edu/pcr/vsrt-ret/Files/Unit4Interference/Interference%20Method%20to%20Measure%20the%20Wavelength%20of%20Radio%20Waves.pdf
and it works at lower frequencies.
It is responsible for some radio interference.

I have manged to convince myself that photons and virtual photons as used in QED are one and the same

I don’t see how you have done that. Strassler makes it clear that they are not - if you understand what he is saying. They are certainly excitations of the same field.

I cant still cant find the link I am looking for 

It won’t help you. There are numerous papers published that don’t pass peer review analysis and are clearly spurious. As has been said here before, just because a paper has been written doesn’t make it correct.

There is a lot of conjecture in this thread. As @evan said to you in a previous life, conjecture belongs in new theories rather than in this part of the forum. There are also a large number of statements made as if they are fact, whereas as @alan has pointed out they are incorrect. Alan has a great deal of experience of practical QM, it’s a pity you’ve driven him away.
At the moment this thread is such a mishmash of cherrypicked ideas and false statements that its value in this section is questionable. You are in danger of flummoxing yourself.

[pensador (OP)]

Quote from: flummoxed on Yesterday at 12:32:21I have manged to convince myself that photons and virtual photons as used in QED are one and the sameI don’t see how you have done that. Strassler makes it clear that they are not - if you understand what he is saying. They are certainly excitations of the same field.

I did a massive response to all your answers above, but when I posted, the website had logged me out.

Basically before starting the thread I already new Maxwells equations did not explain individual photons. So was a little flummoxed that Alan kept bringing them up, with statements like Maxwells equations prove the speed of light is constant, which clearly was not correct along with a few other nit picky other things.

Feynman convinced me not Strassler  that virtual photons and photons have exactly the same properties. In what way are they not? Both transfer momentum and vanish etc.

There are also a large number of statements made as if they are fact, whereas as @alan has pointed out they are incorrect. Alan has a great deal of experience of practical QM, it’s a pity you’ve driven him away. At the moment this thread is such a mishmash of cherrypicked ideas and false statements that its value in this section is questionable. You are in danger of flummoxing yourself.

I think Peter pointed out where Alan was wrong in the link he posted. In all the mishmash, Alan did not introduce Quantum mechanics and spin into the thread, and he didn't post the Matt Strassler link and introduce QED that was all ME.

Alan was not driven away, I was nice to him all along. The little banter you see ref drinking lager, is because he is from down south and made some jokes about people from up north, and Leeds airport, cos ther's no reason to fly anywhere else outside Yorkshire. He also made jokes about the Yorkshire cricket team. I don't live in Yorkshire, but know there are is at least 3 airports you can fly between without having to leave Yorkshire . Alan was wrong yet again     

[alancalverd]

I don't live in Yorkshire, but know there are is at least 3 airports you can fly between without having to leave Yorkshire

I know - I have flown to at least 5 of them. Having been conceived in Co Durham I have the right to consider Yorkshire as a bit inferior, or at least south.

[Colin2B]

I think Peter pointed out where Alan was wrong in the link he posted.

I looked back and couldn’t see Alan posting any link

But I did find this:

In a double-slit experiment with visible light the distance between two slits can be macroscopic, e.g. 0.1 millimeter, or something like that. In order to get an interference pattern, the photon lump should be no smaller than this size.

The photon lump can (in theory) be much smaller than this because it doesn’t need to go through both slits it just needs to be diffracted by one of them.
There is a diffraction angle which determines the separation of the bright bands in the interference pattern, this angle is inversely proportional to the distance between the slits. So, if the distance between slits is large the bands become so close together that they cannot be separated, they just merge.
The crucial point is that photons going through a single slot are diffracted and where they superpose with photons diffracted from the other slot you get interference.

Feynman convinced me not Strassler  that virtual photons and photons have exactly the same properties. In what way are they not? Both transfer momentum and vanish etc.

I did go to the trouble of listing the differences between the properties of virtual and real photons.
If there are differences they cannot be exactly the same 

Glad to see Alan hasn’t left us.

[alancalverd]

The crucial point is that photons going through a single slot are diffracted and where they superpose with photons diffracted from the other slot you get interference.

And this is the holy mystery.

Taylor's experiment showed that you still get an interference pattern when the photon intensity is so low that there is only one photon present at a time, and subsequent experiments show electrons and  atoms doing the same thing.

Now if the projectile really "interferes with itself", a single projectile will end up smeared across the detector, so the energy of the detected "partial photons" will be less than that of the incident photon, and each massive particle event will consist of a partial electron or atom atriking the detector. But these entities have never been detected. Thus whilst the "pilot wave" model predicts the longterm average distribution of photons or whatever, it cannot represent the reality of a single projectile.

Hence my objection to almost every classical or continuum model of quantum behavior. It is fundamentally dishonest and misleading. You have to start with the profound observation that "this is the way stuff actually behaves" and admit that any attempt to model it by continuum mathematics only predicts what happens for very large numbers of events.

[pensador (OP)]

where they superpose with photons diffracted from the other slot you get interference.

Doing the experiment with single photons/particles in seperate locations and bringing the results together displays the same results. With single photons in seperate locations there can be no photon photon interaction or superposition

Here is a good link explaining the history of what we have been waffling on about, with a photo of a photon https://www.zmescience.com/science/what-is-photon-definition-04322/

The basic properties of photons are: from the link
They have zero mass and rest energy. They only exist as moving particles.
They are elementary particles despite lacking rest mass.
They have no electric charge.
They are stable.
They are spin-1 particles which makes them bosons.
They carry energy and momentum which are dependent on the frequency.
They can have interactions with other particles such as electrons, such as the Compton effect.
They can be destroyed or created by many natural processes, for instance when radiation is absorbed or emitted.
When in empty space, they travel at the speed of light.

Gravity isnt mentioned in the link but we know photons are affected by gravity and therefore must also have a gravitational field around them. (not unlike a pilot wave fieldy type of thing  )

Let a source emit a photon at A and it arrive at B where a detector registers it. The particle model states that the photon is emitted at and absorbed at B. No need to re-emit. And this holds for distances from 1 nm to any number of light years.

Am I correct "the superposition of particles is not required to explain the double slit experiment" ? 

The experiment here mentioned preciously by Colin, is interesting. https://www.haystack.mit.edu/edu/pcr/vsrt-ret/Files/Unit4Interference/Interference%20Method%20to%20Measure%20the%20Wavelength%20of%20Radio%20Waves.pdf It leaves a few questions unanswered

Would the experiment be affected by individual photons leaving the emitter from different parts of the emitter at slightly different angles, seperated by microns perhaps. Would the photons trajectory be affected by the atmoshere it is travelling through towards the double slits. Is the photons path as straight as invisaged in the experiment. Fringing affects around the slots are not mentioned. Are there anyother things not considered in the experiment. ??

[alancalverd]

No requirement for a photon to have a gravitational field. Indeed it can't as it has no mass. Please don't make unwarranted assertions - this is physics, not politics. The gravitational bending of light is evidence of gravity warping spacetime.

Also incorrect to say they are particles. Electromagnetic radiation can be modelled as particles or waves. Don't allow outdated classical models to determine your opinion of quantum phenomena if you want to understand physics.

To quote your source 

Not only is light made up of photons, but all electromagnetic energy (i.e. microwaves, radio waves, X-rays) is made up of photons.

which should put you straight on that matter. However some of the rest of the source is poorly expressed and potentially confusing.
 

[Bored chemist]

I dont think radio waves can make a TV screen glow, the same way an electron beam can,

It's a matter of definition
There are about a million YT videos of tesla coils lighting fluorescent tubes.

A solitary electron decelerating as it hits a target is not the same as a radio wave,

It's the traditional way to get Xrays.
Lower energy electrons would produce radio waves- rather inefficiently.

I dont think radio waves can..., or even reproduce a double slit experiment results in the same way a particle can.

Reality doesn't agree with you. It's  high school experiment
http://www.dartmouth.edu/~physics/labs/descriptions/microwave.interference.diffraction/microwaves.writeup.pdf