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I am an electronics engineering major and some questions arise when studying communications technology that utilizes wireless technology. In particular, I am more of a complete picture kind of person, as such I like to see how various things are connected. I want to understand, at least on the surface level, how the following things are connected: Phonons, photons, electrons, charge fields.

As far as I understand things you have phonons. These are quasi-particles representing the quantized energy packets of vibrations through a lattice structure. This seems intuitive enough, and after some further reading I see that photons can be spontaneously emitted from photon interactions resulting from absorption and re-emission of the quantized energy of the phonons. I assume the photon emission frequency/energy is directly related to the energy of the phonon. I believe that photons can also cause phonons when a photon is incident to a lattice structure, though I am not 100% on the details of this.

Photons are actual particles of quantized packets of energy propagating through the EM field medium. As to what exactly constitutes the EM field I am not sure. I believe magnetic fields are due to electrons? I also believe that electrons have an electric field due to the inherent charge electrons pose? However, I believe the charges reach/influence is based on the inverse square law. As such, is the electromagnetic field simply composed on the electron charges as the medium? If this is the case, then how can the EM field be so far reaching?

I apologize for the large amount of questions, and I am sure there are similar questions around, but none that seem to tie all of these things together.

EDIT: To add, am I correct to assume the EM Field is modeled as a continuous distribution of charge, as such the inverse square charge distance is a non-factor? And to answer one of the comments in the question, I have taken classes on partial differential equations, but my physics did not require them, thus I have only indirectly utilized Maxwell's Equations. I assume those will help connect a few of my questions mathematically, so I'll be sure to take a look at those.

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    $\begingroup$ Point charges have the electric field fall off with the inverse square law, but other charge distributions behave differently. For example, the electric field due to an infinite sheet of charge is constant. It doesn't decrease no matter how far from the sheet you go. On a small scale, this is a basis for parallel plate capacitors. $\endgroup$
    – Jim
    Commented Aug 8, 2014 at 18:06
  • $\begingroup$ Forgive me if I am misunderstanding something, but in an uniform surface charge distribution like a capacitor plate, the charge may be equal around the plate but still drops off at the inverse square of the distance away from the plate still doesn't it? The only time I see it not is if you have a continuous 3D distribution of charge... Am I correct in that in modeling the EM field we are treating all charges around us as a continuous charge distribution for simplicity sake? $\endgroup$
    – Jarrod Christman
    Commented Aug 8, 2014 at 19:43
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    $\begingroup$ There seem to be several good questions here. I am wondering if in combination they are too broad. But let me ask, have you yet encountered Maxwell's equations? That might help in knowing where to begin. $\endgroup$
    – paisanco
    Commented Aug 8, 2014 at 23:18
  • $\begingroup$ I have seen them but not worked directly with them. My physics classes didn't require partial diff equations experience (though I have). $\endgroup$
    – Jarrod Christman
    Commented Aug 9, 2014 at 22:26

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Actually the framework where one can describe electromagnetic fields is a classical framework. When one is talking of photons phonons etc one is in the quantum mechanical regime where the concept field, is different.

A classical field in physics:

A field can be classified as a scalar field, a vector field, a spinor field or a tensor field according to whether the value of the field at each point is a scalar, a vector, a spinor or a tensor, respectively. For example, the Newtonian gravitational field is a vector field: specifying its value at a point in spacetime requires three numbers, the components of the gravitational field vector at that point.

The electric and magnetic field are also vector fields in classical physics.

When one goes to the quantum mechanical frame the point in space time is characterized by quantum operators, and to get a vector field one must operate with this operators on the state function of the system.

It aint simple.

Classically the electric field is due to a space distribution of charge, and can be described by a potential. The magnetic field due to the fact that we have never observed magnetic monopoles is generated by magnetic dipoles, or by moving charges . The electromagnetic field, light, is the result of changing magnetic fields and electric fields described experimentally well by the solutions of Maxwell's equations.

Going into the quantum mechanical framework of photons, elementary particles , we know that the classical fields emerge from a huge number of photons whose phases are such as to build up what we see as light/radiation. A single photon is an excitation of the quantum mechanical field which is mathematically defined over all space and is a completely different story than the classical electric or magnetic field

Photons/radiation are emitted in various ways as I explained in answer to a different question. One of them is the energy transfer from the quantized collective kinetic energy in a lattice, phonons, to a photon via interaction with a bound electron. A transition has to happen between energy levels of electrons for a photon to be emitted. Phonons are not the main way photons are emitted (it might be so in black body radiation but I am not sure).

You should read on the links and if really interested attend a course on classical electricity and magnetism first and then quantum mechanics.

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