Faster Than Light?

[exchemist]

I still do not think the guys discussing photons and QED photons in the link I posted were daft people. 

 

This is the most recommended comment on the first thread I posted from research gate discussing photons. Is this what you think is daft, if so why ?

"7th Jul, 2016

Hans van Leunen

Eindhoven University of Technology

Before you start explaining what photons are, it is sensible to consider some contradictions in the current knowledge about photons.

Photons are known to be able to travel billions of light years and can then still be detected by relatively small photon detectors. Waves are not capable of performing that trick. Wave packages disperse when they move. Single waves spread over space and their amplitude diminishes with increasing distance from the source.

The EM field relies on the nearby existence of electric charges. It cannot act as a stable and constant carrier during long distance trips of photons. Thus, quite probably photons are not vibrations or excitations of the EM field. 

However, the set of solutions of multidimensional homogeneous second order partial differential equations cover more than waves. For odd numbers of participating dimensions solutions exist that can be considered as shape keeping fronts and in one participating dimension these solutions also keep their amplitude. These last kind of solutions can travel over huge distances without losing their integrity. 

A significant difference exist between these solutions and EM waves. Also the carrier field will differ. That field must always and everywhere be present. A good candidate is our deformed living space. That field comes closer to the field that we know as gravitation potential.

"

 

I will dig my text book out and see how many pages I would have to scan on QED, no guarantees I am not scanning the entire book. I will also take the opportunity again to reread the section I am thinking about. 

I've told you what I think is daft.

 

I do not see that the quoted passage singles out radio waves as differing from other EM radiation in any way. Radio waves are actually not mentioned. Nor  do I read it as denying that EM radiation is quantised into photons.  

 

What it seems to be saying is that you can't represent a photon accurately as a classical "wave packet" (viz. as  a Fourier series of waves of differing wavelength). That is rather a different point, surely? 

[exchemist]

I am trying to pull together different models to get a more real picture. As I have said before I might be wrong. BUT

 

My understanding is the models are more mathematical than physical. Some believe religiously that the model portrays a physical reality, they do not, they are just approximations, which is what I think you may be agreeing too.

 

The concept of virtual photons transferring forces is not provable (but fits nicely with the model). An electron transfers its forces by its own field, ie an electron without an electric field is not an electron. A moving electron transmits a moving electric field, which radiates out into space as a radio wave. An individual photon with an electric or magnetic field is not a photon. The only similarity is the speed they travel.

 

The moving electric field is variously claimed to be made up of real individual photons or virtual particles. I suspect both these explanations are more mathematical than physical. A radio wave induces a voltage, a polarity in the receiving antennae, as it moves through space. Likewise as it moves through space it is inducing a polarity in the virtual particles momentarily existing in space as it moves, without providing enough energy to cause them to become real. 

 

With enough energy a radio transmitter can separate virtual particles and cause them to become real (dynamic casimir effect comes to mind) but these new real particles are not radio waves, they are real particles in their own right. 

 

I think that to be correct in QED virtual photons should be the term used not real photons, when discussing radio waves. 

No, this is wrong. I defy you to produce any reference that says radio frequency EM radiation involves virtual photons whereas higher frequency radiation involves real ones. The only difference is wavelength - and hence the dimensions of the oscillators that emit and absorb them.  

[exchemist]

I think one of the research gate threads I posted above addresses some of your post.

 

However as you must be aware not all photons are equal in QED, they have different properties, and are not as simple as Einsteins photon. 

 

Thanks all for the exchanges.

 

I have decided to stop posting for a while as I have other things I need to do with my time.

I cannot see anything, in the links you have posted, that draws any distinction between radio waves and higher frequency EM radiation. If I have missed it, you will have to bring it to my attention.