Dear Emmanuel,
"dixitque Deus fiat lux et facta est lux"
I understand that you consider the photon to be the most fundamental in the following sense:
- it was the first type of particle, created from the initial singularity by Hawking radiation, and as a sign of this process you refer to the cosmic microwave background (CMB) radiation
- fermions (including baryon-antibaryon pairs) occurred from photons, via "pair production in two-photon collisions". You argue correctly that, although today we mostly see pair annihilation, somewhere around the Big Bang the conditions favored pair creation enough to obtain fermionic matter.
I understand that when you say that the photon is the most fundamental, you mean that it precedes "historically" other particles, not that it is structurally speaking more fundamental. That is, you do not claim that the electrons are constituded somehow from photons (Louis de Broglie adopted the opposite view, that the photon is composed of two fermions).
- around the Big Bang before the electroweak symmetry was broken, you say that "if the temperature is high enough, the bosons W± and Z0 become photons". You also say "gluons become photons when the temperature reaches a threshold higher than the electroweak symmetry breaking threshold". For these, you refer to Weinberg's book.
Here I confess that, like Florin, I cannot see how the W±, Z0 and gluons were photons. But maybe there is no need for them to be so, as they could be obtained by pair creation just like the fermions.
- to explain the gravity and spacetime geometry as in general relativity, you say "Space and time are measured relative to photons."
- to explain quantum mechanics, you say "If the photon is the most fundamental element in the universe, then it explains the wave-particle duality of matter and it implies that the universe is both continuous and discrete at the most fundamental level."
I agree that the photon has in its blood the laws of quantum theory and relativity. I find difficult to understand which one is the chicken and which one is the egg, to paraphrase you.
Your essay is interesting and pleasant to read. Good luck.
Best regards,
Cristi