# feynman video and photons

Discussion in 'Electronic Design' started by Jamie Morken, Apr 18, 2006.

1. ### Jamie MorkenGuest

I was watching a video of Richard Feynman:

comes from when an electron in an atom drops its orbital energy state
down, and Feynman said that he couldn't really explain where the photon
comes from that made sense in a way of thinking of the photon as a
particle. This seems really basic to me as I don't think of photons as
particles, and so when the moving charge (electron) changes it orbital
state, this is a movement of charge which will create an electromagnetic
field, and because the amount of charge movement is quantized by the
allowable states of the electron orbits around an atom, it will emit a
characteristic amount of electromagnetic energy. Labeling an amount or
frequency of electromagnetic energy to be a photon particle makes no
sense to me. I think a photon is really only a definition of magnitude,
not an actual particle.

cheers,
Jamie

2. ### Guest

Do you feel the same way about electrons?

3. ### Ancient_HackerGuest

Jamie Morken wrote:
I think a photon is really only a definition of magnitude,

Problem with that-- put a candle one foot from a square meter sized
photocell. The photocell has a bazillion little particles of some
photosensitive metal, say calcium, in ultra-fine powdered form. Each
calcium particle is isolated form all the rest.

Let's say you get 10^18 electrons per second out of the photocell.

Now put a x10 filter between the two. So far so good, you now count
10^17 electrons per second. But then harbor-freight-physics has a
sale, and you buy 16 more x10 filters. You put them between the candle
and the photocell.

Now you're getting around one electron per second out of the photocell.

out evenly over a square meter, can cause one electron to jump out.

For a second prize, explain why the electron sometimes jumps out after
1/10th of a second, when the electromagnetic wave hasnt delivered a
full second's worth of energy,

4. ### martin griffithGuest

out of a photocell... you lost me

martin

5. ### martin griffithGuest

ooops, was think of photons , coming out of the photocell

martin

6. ### Bill BeatyGuest

You're wrong; those aren't Nobel-grade discoveries... and apparently
both
photoelectric
effect is not proof of photons. Heh. Everything we know, is wrong.
See:

Lamb W E and Scully M O 1969
The photoelectric effect without photons
Polarization, Matiere et Rayonnement edn
Soci´et´e Fran¸caise de Physique
(Paris: Presses Universitaires de France)

That "Lamb" is WIllis Lamb, who got the Physics Nobel in 1955

texts, such as the misconception that "Einstein's photoelectric effect
proves
the existence of photons." In fact the photoelectric effect can be
explained by
Classical EM fields if we allow vacuum fluctuations to exist. Photons
may
exist, but it takes a much more subtle experiment to prove this. A
good article
on this topic is by the author of the textbook "Quantum Optics" and is
found
in the collection below:

The concept of the photon-revisited
A. Muthukrishnan, M. Scully, M. Zubairy

Found in "The Nature of Light: What Is a Photon?"
Oct 2003 Optical Soc. of Am, Optics/Photonics News
http://www.osa-opn.org/abstract.cfm?URI=OPN-14-10-49

Other papers in the above collection are excellent. The discuss the
real
evidence for photons, and get us questioning the old incorrect textbook
stuff
were taught never to question ...and force us to (gasp) Actually
Think!

Lest you assume that Lamb's paper was the last on this topic, please be
aware that physicsts are STILL arguing over whether EM fields are
quantized
(whether photons actually exist,) and are still looking for experiments
which
supply an unequivocal answer. Zubairy mentions that these issues are
discussed in Quantum Optics, but I've never tracked that one down. The
whole OPA/OSN collection above has lots on this. And a quick google
search turns up a recent paper from 2001:

Proposed experiment to test photon anticorrelation with quantitatively
controllable source emission rate
Abstract
We describe a proposed experiment that will establish whether or not
the
optical field is quantized. We argue that previous attempts to
establish this
have not been conclusive. Quantum optics and Maxwell electrodynamics
predict different outcomes for the experiment which is an improved
version
of that performed by Brown and Twiss in 1956 (Nature 177 27-9). The
Brown-Twiss experiment did not distinguish between the two theories
because its source was classical. In the proposed experiment, a weak
light
signal is achieved without selective deletion, and it can be either
Poissonian
or sub-Poissonian.

Myself, I believe in photons 90%, but have learned enough that I
wouldn't
be suprised if EM fields turn out to be real, and photons turn out to
be
a big and long-running mistake. The last big mistake was the Aether
theory which was shot down by photons. It would be quite ironic if
the physicists of a hundred years hence become convinced that neither
Aether nor photons exist.

((((((((((((((((((((((( ( ( (o) ) ) )))))))))))))))))))))))
William J. Beaty Research Engineer
UW Chem Dept, Bagley Hall RM74
Box 351700, Seattle, WA 98195-1700
ph425-222-5066 http//staff.washington.edu/wbeaty/

7. ### Abstract DissonanceGuest

Photons, EM fields, Electrons, Temperature Gradients, Laplacian, Vector
Fields, etc... have nothing to do with nature. Nature was here long before
man and is not constrained by how man interprets the world and defines
things. Definitions are always circular, Systems can never be completely
understood, etc...

The fact of the mater is that EM fields and photons are just our way of
making something simple out of something that is infintely complex. Its
your choice to choose which one you want to use to try and understand
something or you can even try and come up with another model. Obviously
though what we have today in science is a set of models that have worked
very well... they could be totally off and just by chance we are able to get
something out of them(well, the scientific method is what makes the
difference between science and non-science).

One might define all things in the world as phenomena then find ways to
"understand" that phenomena. The whole point is to predict future outcomes
of similar phenomena so one can use that to there advantage. Quantum
mechanics is based in the realm of probability theory(ofcours along with the
theories it builds off of which involv other branches of math) applied to
real world. Its a model one uses to help predict things.... does it say that
it knows what reality is? It shoudln't. If it does then it is jumping into
the world of philosophy or metaphysics. Its whole purpose is to explain
phenomena. Classical mechanics uses calculus(although a bit of other
branches of mathematics here and there) to explain the world. Both do a
of representation(= math) we can then apply it to the real world(science).

The main thing I'm trying to get across is that all these theories are just
models and try and explain how things work but cannot ever explain how
things really are. We has humans have limited knowledge and are trying to
make sense of the world in whatever way we can.... simplifications make this
possible. If you are working on the theory of elasticity then it doesn't
matter what a real photon is(if you could even know that). If its a small
elf like creature then your crude approximation that it is a spherical
massless particle might be good enough. Ofcourse it a photon could be
totally different but the approximations we give it happen, for some unknown
reason, to work. No one, EVER, will be able to definitively define what
anything is. Some people act like they have a monopoly on intelligence and
in those cases you gotta be careful about what they say. I studied physics
for 4 years and I always thought that what I read and was told was how the
world really was.... I could never except the quantum mechanical based
reality(for obvious reasons because it is based on probability which by its
nature allows is uncertain). When I took quantum mechanics I learned how
probability theory was applied but I still had problems believing that was
how reality really played its game. I finally learned through a prof that
its just a model and they are not claiming that it is really what nature
does(which I always believe but I never heard anyone else say).

So, if you didn't read all that the conclusion is that its up to you to
choose which model you want to use to try and understand things better. The
field interpretation may or may not work better than the discrete element
method. You might even have to come up with your own definitions of things
to get somewhere. In 99% of the cases you will be able to use the
established theories to do what you need. You can rest comfortably knowing
that millions of humans have worked over many centuries to build up these
theories and test there validity. While I personally don't believe in
quantum mechanics being a good approximation to reality I think it is a
natural method to probe deeper into the universe(in the sense that we will
be able to have better predictors).

i.e., LEARN BOTH DEFINITIONS!!!!

Jon

8. ### Ancient_HackerGuest

ok, Mr Lamb was a big name. So were Newton, Kepler, Shockley and
Pauling and they all went far off the deep end near the end of their
careers. Lamb's article has dang few references to it on Google, so
I'll assume it wasnt widely accepted.

Planck, Bohr, Einstein and Feynman all liked the photon theory, I'll
take their word over J. Random Crank Theorist.

9. ### Mark L. FergersonGuest

For light, E=h/f. The relevant factor is the "h", Planck's Constant.
That's why we talk about "photons".

Mark L. Fergerson

10. ### Kevin AylwardGuest

While I personally don't believe in quantum mechanics
Pardon!!!! This makes no sense in relation to what you wrote.

Of course its a good *approximation* to reality. Indeed, its an
excellent approximation. It predicts what is measured in reality
extremely well. Thats why QM exists.

Kevin Aylward

http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

"There are none more ignorant and useless,than they that seek answers
on their knees, with their eyes closed"

11. ### Abstract DissonanceGuest

What I ment is that quantum mechanics is not a good approximation to reality
in the sense that it is not how nature really works. Not that it isn't a
good experimental predictor but that it doesn't "approximate" natures TRUE
methods. Although you might say that they are one in the same it is easy to
give examples where good predictors only look good on some scale but in the
"long run" they fail. If quantum mechanics was one in the same as
nature(i.e., nature used quantum mechanics) then on any scale it would be
the same. Maybe approximation was a bad word to use there but not sure what
else I could use. There are two concepts going on here though... one is the
approximation to nature itself and one is the approximation to the
experiment and predictions. Quantum mechanics surely does do a good job on
the later but this is inherent in its methods(it uses probability and
probably always, when used right, does more good than harm). We can never
hope, at this point atleast, to understand the complexities of, say, a drop
of water by modeling all its particles using the equations of fluid dynamics
yet we can easily model it by using statistical methods. Ofcourse I doubt
the particles themselfs care what method we use or how we think they work...
they will do what they do... its our job to find out how they work and not
there job to work like we want them to.

Note though even though QM predicts SOME things extremly well it doesn't
predict all things well. But sure, if I didn't mention this then I should
have, Theories are used to predict! If they can't predict well then they
tend to be useless(although we can never be sure how close to nature the
theory really is).

For example, Lets suppose you come up with a theory that explains some
phenomena extremly well... lets say 99.9999%. Now I come up with another
theory that explains the same phenomena only to about 30%. Does this mean
your theory is a better representation to what nature uses? Maybe.. maybe
not. My theory could be incomplete or have some errors that make it a bad
predictor yet it could be exactly what nature does(hypothetically atleast).

QM is a bad representative of the what nature does UNLESS you really believe
nature bases itself in the realm of probabilty... I doubt this though but
who knows.

The point is that just because something is a good predictor of experiment
doesn't mean it is how nature works(I might have already said that but). I
do not believe, and it is my personal oppinion, that QM is how nature
works... I doubt it even works by newtonian mechanics. It might even be
impossible to know how it works. My point was to get across the idea that
these are just theories that work well for some things and not explinations
of how reality works. Is it a photon or an EM wave? probably niether...
maybe both... Use what works to get somewhere. If its not working then try
something else...

Jon

12. ### Jamie MorkenGuest

I think you mean h*f

The apparent quantization of aether waves (aka "photons") is a result of
the harmonic states of electron vibrational states in matter atoms.
This doesn't mean that there are particles called photons, this only
means that when matter emits aether waves from electron harmonic state
changes (orbital changes of electrons) it emits the aether waves at
a characteristic frequency based on the geometry of the atom, so it
makes no sense to think there are particles of energy transmission
called photons just because matter emits characteristic energy
signatures. It is like saying that sound is quantized into "speech"
particles because it so happens that there exists humans that emit
sound waves at quantized frequencies.

cheers,
Jamie

13. ### Rich GriseGuest

So, howcome, if you surround an atom with photomultiplier tubes, and
stimulate the atom to "[emit an] eather [wave] from electron harmonic
state changes", only one of the PMTs registers?

Thanks,
Rich

14. ### Mark L. FergersonGuest

No, I wanted to type the usual "Energy equals Planck's constant times
'nu'", but Greek characters don't usually show up properly in
everybody's newsreader. Whatever; we all know how the units have to come
out.
The quantization isn't "apparent", it's "real". To quote your OP:
Since the electrons' orbital energy states _are_ quantized (which is
where Planck's constant actually comes in) the energy of the emitted
photon must also be quantized.

We don't usually see this clearly and consistently because the
orbitals' "natural" quantizations are thermalized, but that's another
quibble. ;>)
There can be, but don't _have_ to be, harmonic relationships.
Nobody ever claimed that "particles of energy transmission called
photons" have any objective existence, they're just a convenient way of
parsing what we measure. And since the matter that emits them does so
from quantized energy transitions, it's quite a natural way to parse
those observations.

Did you have another source of time-varying, self-propagating EM
waves in mind?
No. It's more like saying we can quantize the energy of phonons
because the available energy levels for a lattice that supports them to
vibrate in are quantized. But analogizing between light and sound is a
Very Bad Idea for many reasons. Photons in free space are _not_
analogous to phonons in a lattice.

Mark L. Fergerson

15. ### Mark L. FergersonGuest

Oh, come on Rich, do you expect an "aether wave" addict to be able to
come to grips with wavefunction collapse?

Mark L. Fergerson

16. ### Abstract DissonanceGuest

Who really knows? It could be some other factor involved that makes it
"appear" this way.
I wouldn't be so sure. Many people claim a lot of stuff about physics that
isn't quite true... Some of these people even have phd's in physics. There
are "many" physicists that believe in negative probabilities.. quite
nonsense. Probabilities are taken to be between 0 and 1 by
definition/axiom... so its absurd to say there can be negative probabilities
when we "define" them to be between 0 and 1.. but I've seen several
physicists claim to the contrary. (and its a different story if you want to
define probabilities to be between -1 and 0 or something like that... this
is not what they do though.)
Or it could be that space and time itself is quantized!?!?!

Jon

17. ### Rich GriseGuest

Well, maybe it's more like the atom emits a ray of light, but you don't
know which direction until after you detect it. ;-)

Cheers!
Rich

18. ### Jamie MorkenGuest

Hi Rich,

I think its because the electron orbitals are lobes and rings and so
they emit directionally.

cheers,
Jamie

19. ### Tim WilliamsGuest

Oh, now you've gone and done it.

Besides quantum atomic theory that works quite nicely, what do you have to
say about accelerated electrons? On a bulk scale, sure, you just get
synchrotron radiation, but on a subatomic level, a magnetic force photon
comes in from the magnet, kicks the electron aside (ala Feynman diagram) and
a radiation photon poops out for the change in kinetic energy.

Although I haven't done anything formal with Feynman diagrams, at least
yet... but hey, that's the nice thing about the crucible of Usenet, if I'm
wrong some flamer will correct it ;-)

Tim

20. ### Jamie MorkenGuest

Ya I am having too much fun, I will stop now
If you shoot a stream of electrons through an alternating magnetic
field, like in a free-electron laser, there is an analog relationship
between the oscillation of the free electron and the intensity of the
magnetic field. It makes no sense that a free electron would only
be influenced by quantum amounts of magnetic field energy.

You can change the gap between the two magnet arrays to change the
magnetic force on the electrons to any field intensity, so the
magnetic field energy is not quantized.
(see: "http://en.wikipedia.org/wiki/Free_electron_laser")
I wasn't aware you could do anything formal with Feynman diagrams?

cheers,
Jamie