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...)

K7ITM wrote:
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:

In Feynman's introductory lecture number 1, he
says: "I want to emphasize that light comes in
this form - *particles*." Also: "... light is
made of *particles*." emphasis mine

Feynman's lecture number 2 is titled
"Photons" *Particles* of Light" He says:
"Quantum electrodynamics 'resolves' this wave-
particle duality by saying that light is made
of *particles*, ..." emphasis mine

If I understand it correctly, a cornerstone
concept of QED is that nothing exists except
particles.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:
K7ITM wrote:
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:

In Feynman's introductory lecture number 1, he
says: "I want to emphasize that light comes in
this form - *particles*." Also: "... light is
made of *particles*." emphasis mine

Feynman's lecture number 2 is titled
"Photons" *Particles* of Light" He says:
"Quantum electrodynamics 'resolves' this wave-
particle duality by saying that light is made
of *particles*, ..." emphasis mine

If I understand it correctly, a cornerstone
concept of QED is that nothing exists except
particles.

Cecil, get Feynman's _Lectures on Physics_ Volume I, and
read the entirety of Chapter 38, "The Relation of Wave and
Particle Viewpoints." Quantum mechanics is a very successful attempt,
using statistical methods, to explain the behavior of very small things.
In order to do that, it has to look at those things in very strange
ways. If you want to read about the philosophical underpinnings
you should read chapter 8 of _Quantum Theory_
by David Bohm (a Dover reprint).
73,
Tom Donaly, KA6RUH

Tom Donaly wrote:
Cecil, get Feynman's _Lectures on Physics_ Volume I, and
read the entirety of Chapter 38, "The Relation of Wave and
Particle Viewpoints." Quantum mechanics is a very successful attempt,
using statistical methods, to explain the behavior of very small things.
In order to do that, it has to look at those things in very strange
ways. If you want to read about the philosophical underpinnings
you should read chapter 8 of _Quantum Theory_
by David Bohm (a Dover reprint).

Thanks Tom, I will do that as time permits.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:
Tom Donaly wrote:

Cecil, get Feynman's _Lectures on Physics_ Volume I, and
read the entirety of Chapter 38, "The Relation of Wave and
Particle Viewpoints." Quantum mechanics is a very successful attempt,
using statistical methods, to explain the behavior of very small things.
In order to do that, it has to look at those things in very strange
ways. If you want to read about the philosophical underpinnings
you should read chapter 8 of _Quantum Theory_
by David Bohm (a Dover reprint).


Thanks Tom, I will do that as time permits.
Now consider this! When a quantum of energy, of any wavelength is
emitted from an atom or a nucleus then time and space ceases to exist
for that "wave packet" until it is absorbed again, or passes through a
medium where the velocity of light is less than c (glass for example, or
coaxial cable!!!). Since it is always travelling at c in "space" then
time ceases to pass for the quantum and/or the universe appears to be a
single point from the quantum's point of view.
A possible corrollary of this might perhaps be that there is only one
"real" quantum of a particular energy in the universe at a time!!!
This is pretty well where Relativity leaves Quantum Mechanics I reckon.
Now this may be philosophy but what is the answer that both quantum
mechanics and relativity have for this apparent absurdity?
If it perhaps not so absurd, perhaps this explains some of the results
of the famous single quantum slit experiment?
BTW surely FTL communication only destroys causality if the speed of
information is infinite. Just faster than light by say 1,000 times would
simply mean that it got there faster not before it was transmitted?
Cliff Wright ZL1BDA.

On Sun, 10 Feb 2008 11:41:22 +1300, cliff wright
wrote:

Now consider this! When a quantum of energy, of any wavelength is
emitted from an atom or a nucleus then time and space ceases to exist
for that "wave packet" until it is absorbed again, or passes through a
medium where the velocity of light is less than c (glass for example, or
coaxial cable!!!). Since it is always travelling at c in "space" then
time ceases to pass for the quantum and/or the universe appears to be a
single point from the quantum's point of view.
A possible corrollary of this might perhaps be that there is only one
"real" quantum of a particular energy in the universe at a time!!!

Hi Cliff,

You have contradicted yourself. Your second sentence above has the
premise there is no time. Your last sentence ends with time
explicitly allowed.

This is pretty well where Relativity leaves Quantum Mechanics I reckon.

How so?

Now this may be philosophy but what is the answer that both quantum
mechanics and relativity have for this apparent absurdity?

The contradiction offered.

If it perhaps not so absurd, perhaps this explains some of the results
of the famous single quantum slit experiment?

Dismissing absurdities, the single slit experiment has its own
explanation.

BTW surely FTL communication only destroys causality if the speed of
information is infinite.

As the lawyers would say "FTL communication" is a fact not shown in
the evidence offered here; so the rest of the statement does not
logically follow.

Just faster than light by say 1,000 times would
simply mean that it got there faster not before it was transmitted?

It would be more meaningful to demonstrate it got there 1.00000000001
times faster. If you cannot establish this mark, 1000 time faster
isn't on the horizon.

As one other poster was abashed to discover, you probably could
witness that first demonstration if you were a fish. A fish swimming
in the cooling pond of a nuclear reactor would be hit by a neutron
(one bit of information) before the radiation (light, the other same
bit of information) that catapulted it from the pile. Now, getting
that neutron up to 1000 times faster (in terms of information flow) is
unlikely; but if you were to choose to inhabit a pool of somewhat
greater density (1000 times more so?) - then perhaps arguably so. I
don't think we need hold our breaths and wait for AT&T stock to mature
into Billion$ on that idea.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
On Sun, 10 Feb 2008 11:41:22 +1300, cliff wright
wrote:


Now consider this! When a quantum of energy, of any wavelength is
emitted from an atom or a nucleus then time and space ceases to exist
for that "wave packet" until it is absorbed again, or passes through a
medium where the velocity of light is less than c (glass for example, or
coaxial cable!!!). Since it is always travelling at c in "space" then
time ceases to pass for the quantum and/or the universe appears to be a
single point from the quantum's point of view.
A possible corrollary of this might perhaps be that there is only one
"real" quantum of a particular energy in the universe at a time!!!


Hi Cliff,

You have contradicted yourself. Your second sentence above has the
premise there is no time. Your last sentence ends with time
explicitly allowed.


This is pretty well where Relativity leaves Quantum Mechanics I reckon.


How so?


Now this may be philosophy but what is the answer that both quantum
mechanics and relativity have for this apparent absurdity?


The contradiction offered.


If it perhaps not so absurd, perhaps this explains some of the results
of the famous single quantum slit experiment?


Dismissing absurdities, the single slit experiment has its own
explanation.


BTW surely FTL communication only destroys causality if the speed of
information is infinite.


As the lawyers would say "FTL communication" is a fact not shown in
the evidence offered here; so the rest of the statement does not
logically follow.


Just faster than light by say 1,000 times would
simply mean that it got there faster not before it was transmitted?


It would be more meaningful to demonstrate it got there 1.00000000001
times faster. If you cannot establish this mark, 1000 time faster
isn't on the horizon.

As one other poster was abashed to discover, you probably could
witness that first demonstration if you were a fish. A fish swimming
in the cooling pond of a nuclear reactor would be hit by a neutron
(one bit of information) before the radiation (light, the other same
bit of information) that catapulted it from the pile. Now, getting
that neutron up to 1000 times faster (in terms of information flow) is
unlikely; but if you were to choose to inhabit a pool of somewhat
greater density (1000 times more so?) - then perhaps arguably so. I
don't think we need hold our breaths and wait for AT&T stock to mature
into Billion$ on that idea.

73's
Richard Clark, KB7QHC
Ah Richard! I see where I didn't make myself clear.
There are 2 points of view here (or 2 observers).
For the mythical observer on the "wave packet" as special relativity
tells us, at c time ceases to pass. The corollary of this is that the 40
million years it takes a quantum of light from M104, for example, to
reach my eye at the eyepiece of my telescope does NOT exist from the
Quantum's point of view. Or from another aspect the space between the
galaxy and Earth doesn't exist from the same point of view since it was
traversed in zero time.
From my point of view at relatively zero velocity there is a 40 million
LY gap to traverse in ~40MY but surely if special relativity is correct
this is not what the quantum "experiences" at all. Presumably it
"experiences" emission from an atom in M104 and absorbtion by an atom in
my retina as extremely (perhaps 2x Planck times) close events, unless it
passea through a medium in which the velocity of light is less than c on
the way.

Certainly I agree with you that electromagnetic radiation cannot travel
faster than c in this universe. But that is not to presume that other
forms of energy tranfer may not be possible at higher velocties.
A possible example is "gravitational radiation" which although it is one
possible explanation for certain astrnomical phaenomena has NOT yet been
detected. My research into such instruments as LIGO shows that a major
factor in the hoped for detection is an assumption that this radiation
travels at c. This is neccessary for correlation of signals and observed
events. If this quadrapole radiation travels at some other velocity then
null results are just what one would expect.
The null results of SETI do not surprise me for a similar reason. If
there are advanced starfaring races out there radio or other EM
communication would be woefully inadequate and either not used at all or
only for very specialised (and slow) directional links which are
unlikely to send data towards Earth. If not then we are just an anomally
and we won't be around for long enough to matter on the cosmic scale.
Cliff Wright ZL1BDA

Cecil Moore wrote:

...
If I understand it correctly, a cornerstone
concept of QED is that nothing exists except
particles.

And, if I understand string theory and Dr. Michio Kaku, everything
consists of vibrations--go figure! grin

Regards,
JS