On Feb 2, 2:56 pm, K7ITM wrote:
....
Since this thread started on the premise that a photon is a particle,
which it clearly is not, what did you expect?


"A photon is not a particle."

For those who might seriously wonder why I would make such an
outrageous--some may say idiotic or insane--statement... For those
that haven't dismissed it as lunacy... Let me first point out that I
did NOT say that a photon isn't a quantum. Indeed, I believe that
everything physical in our universe is quantized. But I also believe
that until you really get to know photons (and electrons and neutrons
and various other things we can only sense and never see directly),
you are doing yourself a disservice by calling them by names like
"particle" or "wave." That is because, by thinking of them in that
way, as particles or as waves, you will miss seeing what they really
are. On the other hand, if you call a photon a "quantum of
electromagnetic energy," then you may wonder just what THAT is, and
may get interested enough to study it in the language that describes
it more accurately: the language of quantum theory or the language of
quantum electrodynamics.

I was asked for references. I would suggest as a starting point
Richard P. Feynman's lecture of April 3, 1962, which was an
introduction to quantum behavior. I think the whole of the lecture is
worthwhile, but especially the following paragraph:

" 'Quantum mechanics' is the description of the behavior of matter in
all its details and, in particular, of the happenings on an atomic
scale. Things on a very small scale behave like nothing that you have
any direct experience about. They do not behave like waves, they do
not behave like particles, they do not behave like clouds, or billiard
balls, or weights on springs, or like anything that you have ever
seen."

In the lecture, he offers an example of an experiment that, he says,
you can NOT explain by using either waves or particles, but it's
explained completely and accurately through quantum mechanics. So why
talk about photons as if they are particles or as if they are waves,
when they behave in total like neither? Why not talk about them as if
they are quanta of electromagnetic radiation, which I believe they
are?

There's more about this in other Feynman lectures; there's lots more
about it in the many quantum mechanics texts that are available.
Although the word 'particle' may be used, I believe it's only through
something like quantum mechanics that we can hope to get an accurate
picture of how these entities (photons, electrons, mesons, pions,
etc.) behave.

The question gave me an excuse to refresh my memory about some books
on my own bookshelf:
V. Kondratyev, "The Structure of Atoms and Molecules."
M. W. Hanna, "Quantum Mechanics in Chemistry."
H. A. Kramers, "Quantum Mechanics."
H. G. Kuhn, "Atomic Spectra."
R. E. Dodd, "Chemical Spectroscopy."
In the context of this posting, I did not find in these books a
disagreement with the thought that a photon is not a particle.

You may notice a slight interest in photons there among those titles,
typically photons of shorter wavelength than we generally use on the
ham bands. If you're going to accuse me of not knowing anything about
them, perhaps you should get to know me a bit better first.

I'm quite sure I don't really completely know a photon, on its own
turf. Feynman in that same lecture told us that HE didn't either.
But I do know better than to claim it's either a "wave" OR a
"particle." There are plenty of times I don't have to deal with or
think about its quantized nature to get valid practical answers to
questions dealing with electromagnetic radiation, but there's also no
need to waste time discussing whether a photon is something or other
when it's clear that it's neither.

Cheers,
Tom
(aargh! no! they're coming to take me back to the asylum! HELP!
Now I won't be able to check if there are any responses to this
posting...)