> Let's suppose the aim of the article was indeed to learn PBR from first principles, what would it look like? Quantum electrodynamics?

Something like that, yes. A truly from-first-principles treatment of photon-surface interactions would involve an extremely deep dive into quantum numbers, molecular orbitals, solid state physics and crystal lattices (which are metals), including a discussion about how electron waves superpose to produce various conduction/valence bands with various band gaps, and then discuss how photons interact with these bands.

▲

imadr a day ago | parent [-]

I might be a stupid question but how hard would that be to explain, and to understand?

If you had to teach an alien from another universe physically based rendering:

- In an exhaustive manner and,

- You're only allowed to explain something if it derives from something more "fundamental" until we reach the most comprehensive physical models we have

How hard would be the math behind it for example? Because realistically in my article the hardest piece of math is a very basic integral

Could I for example start reading these Feynman lectures[0] and get up to speed on everything there is to know about photon-surface interaction?

[0] https://www.feynmanlectures.caltech.edu/

▲

delta_p_delta_x a day ago | parent | next [-]

The raw mathematics isn't the hardest; most of this is settled by the end of the second year of undergraduate physics—things like Taylor series, ODEs, PDEs, special functions, a bit of linear algebra (no proofs needed, just use the results); perhaps complex analysis which leads to Fourier transforms and all. Maybe a treatment of tensors.

The issue is the sheer complexity of micro systems, and the unintuitive nature of going deeper than 'EM wave reflects off electrons'.

Consider metal-light interaction. Exactly how does a visible-light EM wave interact with a conduction band of superposed free valence electrons? How does the massive superposition elevate each valence electron up energy levels? Why do only metallic and semi-metallic crystals have no band gap? Why are electrons filled in the order of s, p, d, f, g, h orbitals? Why do these orbitals have these shapes? Why are electrons so much less massive than protons and neutrons? Why does the nucleus not tear itself apart since it only contains positive and neutral particles? Why are protons and neutrons made of three quarks each, and how does the strong interaction appear? Why are the three quarks' mass defect so much more than the individual masses of each quark? How does the mass-energy equivalence appear? Why does an accelerating electric charge produce and interact with a magnetic field, and thus emit EM radiation? What is mass, charge, and magnetism in the first place?

Each question is more 'first principles' than the last, and the answers get more complex. In these questions we have explored everything from classical EM, to solid state physics, to quantum electro- and chromodynamics, to particle physics and the Standard Model, and are now verging on special and general relativity.

	▲	naasking 7 hours ago \| parent [-]
		> The raw mathematics isn't the hardest; most of this is settled by the end of the second year of undergraduate physics—things like Taylor series, ODEs, PDEs, special functions, a bit of linear algebra (no proofs needed, just use the results); perhaps complex analysis which leads to Fourier transforms and all. Maybe a treatment of tensors. It sounds like the OP is saying you could tackle the article if you just know a little high school calculus and trig, and you're here saying that you need years of post-secondary mathematical education. I think you're making his case that he's dramatically simplified understanding how to compute these things for someone who doesn't have a post-secondary education.

▲

chermi 17 hours ago | parent | prev [-]

No, Feynman lectures won't get you there.

	▲	godelski 12 hours ago \| parent [-]
		I think people forget that The Feynman Lectures are aimed at undergraduates. They are great but far from comprehensive.