[RobC (OP)]

Towards the end of his life, Einstein said
"All these years of conscious brooding have brought me no nearer to the question - what are light quanta? Every Tom, Dick and Harry thinks he knows it but he is mistaken.''

[Bill S]

Some questions that come to mind are:

Was this true when Einstein said it?
If so, is it still true now?
Has enough work been done on the subject, in the years since Einstein expressed this opinion, to give us a significantly better understanding of the subject?

BTW. anyone looking for some basic stuff might do worse than to start here:

https://www.brightstorm.com/science/physics/the-atom-and-quantum-physics/light-quanta/

[yor_on]

It's a 'quanta' of energy, and depending on definition of a 'propagation' also having a momentum. And it needs to 'fit' what it hits to 'do work' on it as far as I get https://www.khanacademy.org/science/physics/quantum-physics/photons/a/photoelectric-effect

I don't know why Einstein got stuck on that?

Could be the idea of waves and fields. But it was also so that Einstein wanted some sort of order to the universe, in a old fashioned sense. God doesn't play dice he said. I'm not that happy about 'fields either, from observer dependencies it makes little sense.

[yor_on]

What I say is that, just as Lorentz transformations, you will need to introduce 'something more' to fit 'a fields approach' to a observer dependent universe. And 'dimensions' are questionable.
=

Einstein had a beautifully clear mind. and when he saw something he told his preconception to go f* off. That's where his Nobel prize came from. He got turned in a wrong direction by preconceptions and he never got that chance to draw back and think after his theory of relativity. That's when quantum mechanics became big and he never got room for his own thinking. As i think then.

[Bill S]

Non-mathematician's question:

Does this video say that 10e8 x 10e-7 = 10e15.  If so, is that right?

[yor_on]

hmm, use a addblocker but I guess you want me to confirm something said in some video at that site? F* the videos, read the text. Tell me where you lose it, and we'll see if we both do so :)

[evan_au]

Towards the end of his life, Einstein said

Einstein spent the last couple of decades of his life seeking a unified field theory - and failing.
- He was aware of electromagnetism and gravity
- He was not aware of the strong or weak nuclear forces, so to some extent he was doomed to fail
- He was trying to integrate quantum theory with field theory - and failed. He rejected the non-classical/non-intuitive aspects of quantum weirdness.
- Perhaps today we are more accepting of the idea that "quantum weirdness" is real, and fields are an "averaged" macroscopic representation of the actual quantum behavior that happens on tiny scales.

Today, there has been a fusion of electromagnetism and the weak nuclear force, the electroweak interaction
- Quarks have brought some order to the particle zoo that respond to the strong nuclear force, but it hasn't yet been integrated with the other forces - that requires a grand unified theory (GUT). Experimentation requires particle accelerators larger than anything we have today.
- Gravitation still strongly resists integration with the other forces - and we can't test these ideas without a tame black hole to play with. This would be the subject of a theory of everything (TOE)

So experimental physicists still can't work on integrating quanta of light (electromagnetism) with the 3 other known forces.
Theoretical physicists are still trying to do this integration, playing with things like string theory, but making slow progress.

Why are we all wrong?

Rather than answer the question about why we are all wrong, I have pointed out a few reasons why the experts have not (yet) got it right.

[guest47899]

"quanta - a discrete quantity of energy proportional in magnitude to the frequency of the radiation it represents"

quantum is a supposition about entangled particles that can occupy two separate locations or can be multiple particles occupying a single location. this represents bosonic force attributes with a potential to produce "charged" and uncharged masses that are not limited by hadron restrictions.

when a entangled particle is in two separate locations it functions as a wave or pulsed waves, when multiple particle occupy a single location they manifest as discrete particles within a wave or wave pulse.

a photon can be measured as a discrete particle quantity, E = hf, it is a fermion measurement of a bosonic force which provides it with a hadron particle spin. it has no mass or charge within a wave. because of it's spin value of 1 which is attributed to quarks, it cannot be at rest. Yet quarks themselves have mass, charge and spin. Somehow, three quarks and a gluon, via cancelation produce a discrete photon energy particle with a haydron
value.

a light wave viewed as entangled particles provides a construct from which to develop kinetic energy wave theory. EM light with a bosonic spin value of 1, entwined with Gravities baryonic spin of 1/2, create the kinetic energy that fuels the Galaxies of the Universe.

 

[alancalverd]

Why did Einstein say that? Because it's true.

90% of correspondents on this forum will assert "light is a particle", "light is a wave", "light is a wave until it is observed" etc.....none of which is true.  Fact is that we can model light as a wave or as a particle.

[jeffreyH]

There is wave mechanics (Schrödinger's model) and matrix mechanics (Heisenberg's model).

And not forgetting the Dirac delta function that is not a function at all!