Nature of electromagnetic waves

Question

EM waves are defined as a propagating disturbance of the EM field. But aren't the waves simply a mathematical concept, i.e., analogous to the oscillating (increasing and decreasing) strength of the field as opposed to actually consisting of a physical thing moving up an down?

Answer 1

First there has to be defined what are photons, electromagnetic radiation and EM waves. Secondly it has clearly to be difference between a quantum mechanical point of view and a classical.

1. What are a photon, EM radiation and EM waves?

   A photon is a undivisible quanta, which is emitted from excited elementary particles. The photon emission from any body is called EM radiation. The Black body radiation is the best example for the steadiness of the frequencies of the emitted EM radiation in the macroscopic view and the proclamation of the emission in packages by Planck in the view on atomic level.

   

   Planck' law from Wikipedia

   EM waves are modulated EM radiation such like in radio waves. The misunderstanding in the three termina comes from the fact that photons have an electric and a magnetic field component and this components oscillate during the propagation along their trajectory. The extend of this fields coudn't be infinite because otherwise the formation and the collapse of every peak would be happen with infinite speed. In Radio waves the emission of the photons happens nearly synchronious and since we are able to measure the near field of an antenna we are able to see how the field components of the photons are build.

   

2. Quantum mechanics and macroscopic processes

   Quantum mechanics ... is a branch of physics which is the fundamental theory of nature at small scales and low energies of atoms and subatomic particles.

   The generalization of QM from the subatomic level to macroscopic process lead to the understanding of a overall existing electric and magnetic field and the excitation of quanta in this field. An aether and particles in it. The understanding that photons have to be seen only in the context of the gravitational field gets lost in this case. But wasn't it a big contribution of Einstein that there is no need in any aether?

So your statement

EM waves are defined as a propagating disturbance of the EM field.

is well for the representatives of QM for macrocopic processes but overshadows the classical view.