Interference between two microwave transmitters cannot be
explained with the "photon" theory of electromagnetic
radiation (emr). This theory cannot be a true
representation of Nature, and so should not be used to
evaluate observations or other theories.
Long version:
As best I can tell, the generally accepted definition of a
photon involves:
1  The photon begins when quantum of energy is lost,
somewhere, in one specific location  such as an
electron dropping an energy level in an atom.
(Actually, I think conventional photon theory may
allow for probability distributions for when and where
the photon began. Also, a highly coherent photon
involves a long time period for the long series of
sinusoidal oscillations to be transmitted.)
2  The resulting photon contains that exact quantum of
energy. Therefore, all electromagnetic radiation is
quantitised.
3  The photon propagates as electromagnetic radiation
with a frequency proportional to the quantum of
energy it carries.
4  Somewhere, the photon delivers this quantum of energy
 typically to a single electron. That's the end of
the story  the photon no longer exists. ("Collapse
of the wavefunction" etc.)
5  So the photon begins at one point and ends at another.
6  The relationship in time and space between the
starting point and the end point makes it clear that
the photon operates as a wave as it gets from one
place to another.
7  Photons do not interfere with each other  but the
wavefunction of an individual wavefunction does
interfere with itself. Consequently, the
probabilities of where photons will deliver their
energy in any experiment are not affected by the
number of photons in the system. (Except in nonlinear
media.)
8  Photons are real things  not just a handy theoretical
construct. They are the means by which the
electromagnetic force gets from place to place. This
is for changing and oscillating electromagnetic forces
and for "static" forces such as a magnet sticking to
a fridge, electrons on one plate of a capacitor
affecting electrons on the other plate (there's no
fundamental difference between this and sending light
or gamma rays across the Universe for billions of
years) and for all radio, optical, Xray etc.
interactions. Consequently any proposed mechanism,
such as for nonDoppler redshift, can be discounted if
it is incompatible with what we think we know about
"photons".
9  Photons are massless "particles".
10  A photon carries momentum  in proportion to its
energy.
There may well be other common beliefs about "photons",
such as to do with their polarization, spin etc. Can
anyone point to a similarly detailed list of what most
people understand by the term "photon"?
There are a number of other peripheral and consequent
beliefs about photons. For instance, the question of how
the photon "knows" where it will land  perhaps at the
time it is first radiated. This is related to the
perplexing question, photons or not, of momentum deposition
at the source of isotropic light when we believe that in
the whole system a single quantum of energy has been
received at some specific location, quite some time after
it must have emanated "isotropically" from the source.
I understand that the concept of a photon  not by name
originally  came from Einstein. It has been supported by
many greats of the field, not least Richard Feynman. I
understand it is an attractive concept when dealing with
Xrays and emr where we can detect or imply an individual
quantum of energy is involved and/or measure the momentum
of an emitted, absorbed or scattered "photon". But this
doesn't mean that the "photon" model accurately represents
Nature.
Critics include Willis Lamb, who wrote a paper
"AntiPhoton" in 1995, which I can't find on the Net or
at the journal site. He wrote, in his most recent paper
(2001  Super classical quantum mechanics: The best
interpretation of nonrelativistic quantum mechanics):
> In case you don't know it already, despite what many
> other people think, THERE ARE NO PHOTONS OF A
> PARTICLELIKE NATURE IN QUANTUM ELECTRODYNAMICS.
(Lamb's capitalisation.)
See also the talkingto he gave the delegates to the 1995
US Army workshop on quantum cryptography and computing:
http://www.aro.ncren.net/phys/proceed.htm
I expect any emr theory such at that of "photons" to either
apply completely from static situations to gamma rays
(DC to daylight and beyond) or to include some specific
limits beyond which it does not apply, and to point to some
other approach should be used instead. I have never heard
of such a limit, and when I believed in "photons", I used
to think that an electron and a nucleus, or my fridge and
one of its magnets, were continually exchanging "photons".
Before I make my critique, I want to point to some other
possible ways in which the "photon" concept could be shown
to be inadequate.
There are many critiques to be made of "photons" in such
low frequency or static situations. There are critiques
to be made in the three polarizer paradox  but photon
proponents get around that by saying a photon at one
polarization can be considered to have a superposition of
polarizations at a range of angles (except 90 degrees),
which the middle polarizer can select from to produce a
polarization which in turn has superposed polarization
states which pass the third polarizer. For instance:
Polarized Light and Quantum Mechanics: An Optical
Analog of the Stern=96Gerlach Experiment
Joseph M. Brom,=86 and Frank Rioux=87 2002
http://www.users.csbsju.edu/~frioux/polarize/740200jb.pdf
It was my understanding that most people consider that a
polarizing sheet can only absorb a "photon"  that the
sheet can't change the photon's polarization. But if
"photons" are considered to have a superposition of all
polarisation states except those at 90 degrees to their
official state, then I think the "photon" concept can be
made to do pretty much whatever people want. I think this
adds no explanatory or predictive power to the classical
view of emr polarisation  and is far less elegant.
My critique is on familiar ground: interference. I use
twoslit interference, but the same arguments hold for most
system of lenses, mirrors, multipleslit interference,
holograms, zoneplates etc.
A twoslit interference experiment involves a monochromatic
wave emanating to a barrier and a fraction of the wave
passing through the two slits in the barrier  with a
measuring arrangement for the resulting deposition of
quanta at a distant screen.
Open slit A and we get X quanta per second per unit area
in the part of the screen where the diffracted light from
this slit illuminates the screen reasonably evenly. Close
slit A and open slit B and we get the same pattern, offset
an insignificant amount due to the distance between the
slits.
Open both slits and we get overall, twice the number of
quanta per second per unit area at the screen, but the
resulting interference pattern causes some locations to
receive 0 quanta and others to receive 4 times the number
they received with a single slit.
Since we know the quantum of energy which is always
deposited for this particular frequency, we can turn down
the lightsource to the point where most of the time there
can't be more than one "photon" in the system  and we
observe the same statistics about where the quanta are
deposited. Therefore, we conclude that if "photons" exist,
then each photon's wave properties involve interference
with itself, and do not seem to be affected by the presence
of other "photons".
With this traditional experiment, there is a single source
of light, and we say that this is the source of all the
photons. The photon model correctly describes the
observations  because there is a single source and a
single endpoint for each photon, where the statistics of
the locations of of the endpoints seem to be controlled
by each photon's wavelike properties.
Since photon theory has no explicit frequency or wavelength
limits, we should be able to apply it to radio waves too.
Lets say I have a 10GHz oscillator, with a small antenna.
This produces emr with a 3cm wavelength. According to the
photon theory, this emr is composed of vast numbers of
individual photons, each carrying a small quantum of
energy. 1.243 micron emr deposits quanta of 1 electron
volt, so each 10 GHz "photon" carries 41.4 micro electron
volts of energy. We can't detect such a small individual
quantum of deposited energy, but all the evidence leads us
to believe that emr of this frequency can, or will always,
deposit individual quanta of this energy. According to
the photon theory, each such quanta of deposited energy
arises from a similar quantum which is lost in the
transmit antenna.
At a distant "screen" or observing line, perpendicular to
the path from the transmit antenna, I have a 10GHz receiver
which I can use to measure energy deposition at various
points line. The receiver could be an electronic amplifier
or it could work by detecting temperature changes in an
absorbing screen due to the deposition of quanta.
In the central area of the screen, I observe an energy
density  which I reasonably conclude means X 41.4ueV
quanta per second per unit area.
Now I invent a second identical transmitter and place its
antenna close to the first one. These transmitters have
independent power supplies and oscillators, but they both
run at 10GHz, with an accuracy of (for instance) 0.01 Hz.
I think this accuracy is practical with a phaselocked
loop from an atomic frequency standard.
As with the twoslit experiment, the overall energy
deposition ( =3D number of quanta per second) doubles at the
detecting screen. Likewise, the number of quanta per
second goes down to 0 in some locations and up to 4 times
the single transmitter value in others.
According to my understanding of "photons", this experiment
does not allow a "photon" to interfere with itself, since
a photon can only arise from one transmit antenna or the
other. Yet we observe perfect interference. So I say
this proves that the "photon" theory is wrong. The theory
could only account for the observations if it was rejigged
to allow a photon to arise simultaneously from two places
at once, or to allow two photons to interfere with each
other.
The second possibility is excluded by turning down the
transmit power to the point where we reasonably conclude
that there is usually no more than one "photon" in the
system at any given time. We still see the interference
pattern. So the only way a "photon" theory could describe
this is to modify it to allow a "photon" to arise from two
or more places at the same time. This would leads to
problems in deciding how much energy was lost at those
sites and would result in a theory very different from the
current one.
Lets tweak the experiment. Firstly, lets imagine that one
transmitter is running 1Hz faster than the other. We
would still observe interference, but the pattern would be
moving by one fringe per second. Only when the detuning
and therefore the fringe movement got so high as to prevent
us from detecting the interference pattern would we say
that there might be no interference. However, this is a
purely practical matter. If we had a 10 GHz transmitter
interfering with an 11 GHz transmitter and a set of
receivers we could move fast enough (or create a suitably
moving detection pattern) to keep up with the billion
fringes per second movement of the pattern, we would be
able to detect it just as well.
Secondly, lets increase the frequency of the transmitters.
I am not sure how fast electronics go these days, but I
guess up to frequencies of 100 GHz or so  3mm wavelength.
This experiment could be made to work fine at those
frequencies too. Now the quanta being deposited are 4.14
milli electron volts  but we probably still don't have a
way of detecting them individually.
We can detect near visible infrared quanta  with
photographic film and silicon photodiodes  but this
involves frequencies where we need lasers, rather than
electronic oscillators, as transmitters.
I imagine it is possible to lock the frequency of a laser
to an electronic reference. Maybe it would be possible to
have lasers interfering detectably when they are locked to
a single lower frequency clock, or to two clocks derived
from two independent atomic references.
Two lasers synchronised from a third would interfere fine,
but then we get into arguments about a single source of a
"photon" and how this leads to the stimulated emission of
other identical "photons".
So far, we have considered monochromatic sinusoidal emr.
I think the two microwave transmitter experiment shows
that the photon theory is invalid, because the theory
insists that each photon must originate from a single
quantum at a single location.
Here are some other critiques.
Photon's can't be "massless". Saying they are "massless at
rest" is pointless, since they cannot be at rest.
We have a sealed tank sitting on some scales and inside the
tank is a battery operated xenon, laser or LED flash
arrangement which puts out a bunch of light much shorter
than the length of the tank. Chemical energy in the
battery (in the form of electromagnetic energy  perhaps
"photons"  in the bonds and electron energy levels) is
converted into electronic energy in a capacitor (more em
energy, perhaps "photons") and then into light which
traverses (as emr, perhaps as "photons") from the left
end of the tank to the right end, where it is absorbed,
heating the material there (kinetic energy of atomic
movement and "photons" of greater forces as these atoms
jostle each other more).
While the light is in flight, it is temporarily decoupled
from the body of the tank, but as soon as it is absorbed,
the gravitational effects on that light would result in
it falling downwards, leading to a vertical force when
the light is absorbed by the tank. So the overall
weight/mass of the tank would not change, although there
might be a temporary loss and then a shortterm gain as
deviations from average, just as if someone had thrown a
ball from one end of the tank to the other. We believe
that while the light was in transit, the battery and
capacitor had a lower mass then before it was emitted,
and the receiving wall on the right had a lower mass than
after the light was absorbed. No energy or matter has
escaped from the tank  so the only reasonable
explanation is that the light has mass.
So how can anyone maintain that light or other emr has no
mass? It doesn't matter whether or not the emr is is
considered to be photons. My understanding of the photon
theory is that "photons" are the sole mediating mechanism
for the electromagnetic force, so all chemical energy, and
all the energy of a spring etc. is composed entirely of
electromagnetic forces, in the form of "photons". A taut
spring or a charged battery has more energy and as far as
we know (it may not be measurable) it has a
correspondingly greater mass. So the idea that "photons"
have no mass is provably wrong. (I believe that if a beam
of light is shone past the Sun and so is bent by the Sun's
gravity, then the Sun itself is attracted and slightly
moved towards the beam.)
I understand that the traditional view of photons is that
each one has a specific wavelength / frequency  and
therefore quantum of energy. Are there any exceptions to
this view? Do some theories involving photons allow for
a probability distribution for the photon's wavelength?
My view is that various processes, including quite often
the loss of a specific quantum of energy, give rise to
electromagnetic radiation. Then, this emr is subject to a
number of processes as it travels in vacuum or other
media. It can spread out and so become less concentrated.
It can be focussed with a lens, mirror or diffraction
device such as a zoneplate. It can be split into two
beams by passing into a block of material with a different
refractive index. It can be partially absorbed. It can
be divided and parts of delayed in time and then later
mixed together with other timedelayed parts of the emr.
It can be distorted in the electrostatic / magnetic
dimension. It can add and subtract from other sources of
emr. (There are polarization processes too.)
If we consider emr which arises from a specific quantum of
energy, ala photon, it seems to me that this emr carries
with it either the whole amount of energy and momentum, or
the probability of this energy and momentum. But when the
emr is mixed with other emr the resulting patterns of
energy deposition depend on all the relevant sources
and how they interfere at each point which could absorb
them.
We observe that there is a direct relationship between the
frequency spectrum of the emr and the distribution of
energies in the quanta it deposits. A sinewave leads to
only one energy level. A single arbitrary shaped pulse
creates a particular and easily predicted probability
distribution for the relationship between quanta energy
levels and the number of such quanta deposited.
So I think the quanta which may have given rise to the emr
do not necessarily have anything to do directly with the
quanta which are deposited.
We know that two very low energy independent microwave
transmitters result in quanta being deposited in some
places at 4 times the rate which results from a single
transmitter.
Just because we usually observe things by amplification
mechanisms which round off energies to exact quanta doesn't
mean that the real nature of emr is also quantitised.
Maybe it just transfers probability from one place to
another, and this probability carries, on average and in
general the momentum and energy. I can't see any other
explanation. Sine the source of the emr can be destroyed
and the emr be in transit well before its destination
absorber has been brought into existence, the energy and
momentum clearly resides solely in the emr. In the case of
a short impulse with spectral qualities the same as black
body radiation from the Sun, the whole wavefront may be
only a few microns deep. This carries the energy and
momentum, and it exists independent of anything else, in
this small area of space, moving at c.
Maybe when the coupling between the source and all possible
destinations is very close (a small fraction of the
wavelength  which covers all "static" electromagnetic
situations, in which the wavelength is "infinite") there is
a direct 1:1 relationship between a quanta being lost and
the quanta being deposited. But in situations like cyclic
or pulse emr, the quanta (or multiple quanta) loses its
energy to space and this radiates away, carrying a
probability of energy and momentum. These emr waves can
interfere with the emr produced by the loss of other
quanta and result in quanta being deposited which result
from combination of the probabilities / energies /
momenta of the various emr waves interfering at that spot.
So how does a really dim emr signal (from one source or
from the interference of multiple sources) occasionally
result in the deposition of a fullblooded quantum of
energy, when as far as we know it is the same dim signal
which has been illuminating that atom, electron etc. for a
long time in the same way without any such deposition? Why
can we expose the film for a very short time indeed, such
as 0.001 second, and occasionally get (as far as we know) a
fullblooded quanta which changes an electron's energy in
an atom in a silver iodide crystal  even when on average
such a quanta would be deposited only every 1000 seconds?
Stochastic Electrodynamics (SED) invokes a "vacuum energy"
to explain this. I am still trying to understand QM but it
seems that some conventional QM theories involve vacuum
energy too. This has its problems, but it seems like a
better approach than my understanding of conventional
photonbased quantum mechanics: that all emr consists of
independent, totally quantitised "photons" and that each
photon spreads out potentially over the entire Universe,
and magically disappears everywhere else once it deposits
is singular quantum of energy somewhere, sometime, in
exactly one spot.
I see no problem with classical emr and interference
doubling the amplitude of two signals in some locations,
leading to twice the current at twice the voltage into the
load, resulting in quadrupling the energy deposition. The
challenge is to reconcile this this with the observation
that emr of a particular frequency always (as far as we
know) results in deposition of specific quanta of energy.
Since particles (electrons, neutrons, helium atoms and
now Buckyballs) exhibit spatial patterns in their
probability functions just like emr (as evidenced by
interference experiments)  and (I understand) with exactly
the same relationship between the spacing of these
patterns in a vacuum and their momentum I suspect this
"frequency ~ energylevel ~ momentum" stuff is a property
of space, not of matter or electromagnetism.
[snip... ]
> I am not sure how fast electronics go these days, but I
> guess up to frequencies of 100 GHz or so  3mm wavelength.
NEW MATERIAL STRUCTURE PRODUCES WORLD'S
FASTEST TRANSISTOR, April 11
A new type of transistor structure, invented by scientists at the
University of Illinois at UrbanaChampaign, has broken the 600
gigahertz speed barrier. The goal of a terahertz transistor for high
speed computing and communications applications could now be
within reach. Full story at http://www.physorg.com/news3662.html

I like cats, too. Let's exchange recipes.
Short answer.
I agree that the photon is really a wave and not a point particle.
In fact I would go further and say all particles are waves.
However that doesn't mean that a description using point particles isn't
an immensely powerful technique that allows the solving of a wide range
of difficult quantum mechanical problems. It is.
So people us it. Lots and lots of people.
They are cleverer and more knowledgeable than you and me.
Longer answer....
The wave formulation (as far as I can tell) is mathematically
intractable and very difficult to use for real problems of significant
complexity.
Inevitably those regularly manipulating QM as a probability wave of
point particles have a working image of point particles in their mind
that assists them in expressing the maths. It should not be surprising
that this is a potent description as far as they are concerned. IT has
the benefit of delivering the right answers, too.
IMHO the dichotomy derives in part from ignoring the reality of
detectors. Photon detectors are typically large massive (ie contain much
energy) and thus highly localised particles like atoms. This leads
people to imagine photons as little bullets that hit equally tiny atoms,
instead of vast waves (of wavelengths thousands of times larger than the
emitting/absorbing atom) interacting with tiny atoms. This seems to be
intuitively less stressful to imagine, suppressing the QM fact that a
particle localised precisely at a point, will have infinite momentum.

Oz
This post is worth absolutely nothing and is probably fallacious.
Use o...@farmeroz.port995.com [ozac...@despammed.com functions].
BTOPENWORLD address has ceased. DEMON address has ceased.
Short answer:
You have some misunderstandings of the theory. Most of them are in the
form of general statements of the sort that are often used to describe
the theory in nontechnical language, but are not adequate for an in
depth look.
I will answer in detail only the points you would learn the most from.
> 1  The photon begins when quantum of energy is lost, somewhere, in
> one specific location  such as an electron dropping an energy level
> in an atom. (Actually, I think conventional photon theory may allow
> for probability distributions for when and where the photon began.
It also allows for a quantum superposition. A superposition is *almost*
exactly like a probability distribution. The difference is that they
have "amplitudes", which are just like probabilities except that they are
complex numbers instead of positive reals. You can get probabilities
from them by taking their squared magnitude, so in a sense a
superposition is a square root of a probability distribution.
> 7  Photons do not interfere with each other  but the wavefunction
> of an individual wavefunction does interfere with itself.
> Consequently, the probabilities of where photons will deliver their
> energy in any experiment are not affected by the number of photons in
> the system.
This oversimplification seems to give you the most trouble.
Photons are indistinguishable from one another in a fairly absolute
sense. One can reasonably talk about two photons, but not about photon A
and photon B.
Several of your problems below disappear if you stop trying to
distinguish between different photons.
Photons are not necessarily independent. There are situations in which
knowing where one photon was detected tells you a lot about where
another will be.
> See also the talkingto he [Lamb] gave the delegates to the 1995 US
> Army workshop on quantum cryptography and computing:
>
> http://www.aro.ncren.net/phys/proceed.htm
I suggest you take his first point to heart:
Lamb:
> Anyone wanting to discuss a quantum mechanical problem had better
> understand and learn to apply quantum mechanics to that problem.
Robin Whittle wrote:
> But if "photons" are considered to have a superposition of all
> polarisation states except those at 90 degrees to their official
> state, then I think the "photon" concept can be made to do pretty
> much whatever people want. I think this adds no explanatory or
> predictive power to the classical view of emr polarisation  and is
> far less elegant.
As a counter example I would suggest the Aspect experiment or it's
variants, but I don't think you are ready for them yet.
[Snipped description of two slit experiment performed with two microwave
transmitters]
> According to my understanding of "photons", this experiment does not
> allow a "photon" to interfere with itself, since a photon can only
> arise from one transmit antenna or the other. Yet we observe perfect
> interference.
Indeed we do. But the indistinguishability of photons means we can't
discriminate between photons from one source and those from the other.
According to quantum mechanics, photons from different sources *can*
interfere.
Even when there is only one photon, two possible sources of that photon
can interfere. (I'm leaving out some fine print)
> We can detect near visible infrared quanta  with photographic film
> and silicon photodiodes  but this involves frequencies where we need
> lasers, rather than electronic oscillators, as transmitters.
Interference between separate lasers has been done.
> Photon's can't be "massless". Saying they are "massless at rest" is
> pointless, since they cannot be at rest.
Would you rather people said "photons have no rest mass" instead?
It makes things simpler to think of photons (and other particles that
can never be at rest) as having a rest mass of zero. It never causes any
problems (except confused questions). The equations that describe
particles with well defined rest masses also work for particles that
travel at the speed of light, but only if you use 0 for the rest mass.
I any case, when we say photons are "massless", we *mean* rest mass. We
all know that a box full of photons (e.g. with perfect mirrors on the
inside) will weigh slightly more than an empty box.
> I understand that the traditional view of photons is that each one
> has a specific wavelength / frequency  and therefore quantum of
> energy. Are there any exceptions to this view?
This view is actually a very special case, and can never be perfectly
realized in practice.
Only an ideal laser (which must run for all eternity) can produce
photons of an exact wavelength.
> Do some theories involving photons allow for a probability
> distribution for the photon's wavelength?
There is really only *one* such theory, and it does. Not only
probability distributions, but quantum superpositions.
Ralph Hartley
> Short version:
>
> Interference between two microwave transmitters cannot be
> explained with the "photon" theory of electromagnetic
> radiation (emr). This theory cannot be a true
> representation of Nature, and so should not be used to
> evaluate observations or other theories.
[huge snip]
[more huge snip, your really are too longwinded]
Your misunderstanding lies in the assumption
"since a photon can only arise from one transmit antenna or the other"
that a photon must come from one or the other antenna.
If they interfere, you can't tell, and conversely,
if you can tell (by detecting their emission for example)
they won't interfere.
There is no fundamental difference here
with the standard explanation of the twoslit experiment.
Best,
Jan
PS No need to go to microwaves:
two identical (stabilized) lasers set to have their beams overlapping
will also produce interference patterns,
within the limits of their phase stability.
Yikes! Quite a rant about photons. I suspect that you might have
"tricked" yourself into believing photons are something other than what
QED describes them as. However, some of the points you make that I
snipped, I might agree with but it is just too long.
 Stochastic Electrodynamics (SED) invokes a "vacuum energy"
 to explain this. I am still trying to understand QM but it
 seems that some conventional QM theories involve vacuum
 energy too. This has its problems, but it seems like a
 better approach than my understanding of conventional
 photonbased quantum mechanics: that all emr consists of
 independent, totally quantitised "photons" and that each
 photon spreads out potentially over the entire Universe,
 and magically disappears everywhere else once it deposits
 is singular quantum of energy somewhere, sometime, in
 exactly one spot.
IMHO, SED would work much better if we reinstitute a modified
Diraclike Sea and take vacuum polarization up to tree level. A
relativistic medium concept of bound charge but the medium is in a dual
spacetime situation. SED is trying to make do with not enough energy
because it only seems to rely on the "vacuum" EMR and not "vacuum"
fermionic charge (taken up to tree level). You can see more about this
concept at the link below. In this kind of relativistic medium picture,
spacetime can be modeled in a similar fashion to GR. Spacetime with
respect to charged particles is curved or "tilted" wrt other charges.
So photons are somewhat a description of this curvature. A single
photon does not "spread out" over the entire Universe. EMR does that;
as you go further away from the source, you merely have less photons per
area. Now if a photon is just a "wavicle", what keeps it from
dispersing in the relativistic medium? This, I think, is the big reason
for the particle concept for photons. But more is being understood
about how photons can be more like "wavicles".
 I see no problem with classical emr and interference
 doubling the amplitude of two signals in some locations,
 leading to twice the current at twice the voltage into the
 load, resulting in quadrupling the energy deposition. The
 challenge is to reconcile this this with the observation
 that emr of a particular frequency always (as far as we
 know) results in deposition of specific quanta of energy.
I do believe this has been reconciled. See Milonni's "The Quantum
Vacuum: An Introduction to Quantum Electrodynamics".
 Since particles (electrons, neutrons, helium atoms and
 now Buckyballs) exhibit spatial patterns in their
 probability functions just like emr (as evidenced by
 interference experiments)  and (I understand) with exactly
 the same relationship between the spacing of these
 patterns in a vacuum and their momentum I suspect this
 "frequency ~ energylevel ~ momentum" stuff is a property
 of space, not of matter or electromagnetism.
In our relativistic medium viewpoint (and for that matter, the Standard
Model) there is not so much difference between spacetime and matter.
Their geometrical configuration is just different. In the case of a
free space photon, I believe the electromagnetic properties do come from
spacetime. A free space photon really only has momentum and helicity
as intrinsic properties so that only leaves bound spacetime, quantum
"vacuum", fermionic charge = +, sqrt(hbar*c) for a photon's EM
properties to come from.
For an alternative way of describing free space "real" photons
semiclassically, see the link below. It works pretty good. One
problem we still need to work out is the observer dependent transverse
lengths. Scratching my head on that one. ;)
FrediFizzx
http://www.vacuumphysics.com/QVC/quantum_vacuum_charge.pdf
or postscript
http://www.vacuumphysics.com/QVC/quantum_vacuum_charge.ps
Particularly consider the idea of a photon bouncing between two mirrors
to make a clock, all this moving at relativistic speed. Look at the
photon from the two frames and there is a contradiction. Something has
gone wrong.
The waveparticle duality is a mystery. No one seems to have any idea
what is behind it.
IMHO its a wave (in fact all particles are waves) that is particularly
conveniently described in a tightly constrained highly specific particle
formulation.
>Particularly consider the idea of a photon bouncing between two mirrors
>to make a clock, all this moving at relativistic speed. Look at the
>photon from the two frames and there is a contradiction. Something has
>gone wrong.
>
>The waveparticle duality is a mystery. No one seems to have any idea
>what is behind it.
Indeed, a problem.
To my own satisfaction I am content with the description that all
particles are waves, but essentially all detectors are quantised systems
(eg an atom) and the quantum nature derives from the quantum nature of
detectors. So far I haven't seen an adequate contraindication of this
position. The photoelectric effect is inherently quantised since it
relies on a tuned resonant system.
[NB I just noticed the original poster was not aware that photons from
different sources can and do interfere. Both lasers and radio
transmitters of adequate stability.]
>A single
>photon does not "spread out" over the entire Universe. EMR does that;
>as you go further away from the source, you merely have less photons per
>area. Now if a photon is just a "wavicle", what keeps it from
>dispersing in the relativistic medium? This, I think, is the big reason
>for the particle concept for photons. But more is being understood
>about how photons can be more like "wavicles".
I was trying to avoid a discussion about waves and photons....
After all I just get blinded by serious maths whenever I try.
However I do not accept that this is a valid argument.
1) For any give emission of a photon by an atom we can locally obtain
the direction of emission from the recoil of the emitting atom (to some
level of accuracy).
2) This concludes the description as far as the emission is concerned.
3) Similarly for any given absorption (why is this not spelled
absorbtion to go with absorb?) we can locally obtain the direction the
photon came from by measuring the recoil.
4) This concludes the description as far as absorption is concerned.
5) We note that (1) is the timereversed description of (3).
Following the ageold technique of physicists we model this by sweeping
as much complexity under the carpet and combining the two pictures by
postulating an unobserved particle with the properties of a photon. Its
a transmitted chunk of energymomentumspin. Much like a neutrino....
Unfortunately this description is just that, a description, and isn't
much help in predicting. Predictive techniques have been developed..
Even worse I suspect that a QM description of a single photon with a
reasonably welldefined momentum (ie direction) would be somewhat non
trivial to set up. A complex function of an infinity of states with
expectation one, whether its done in particle or wave formulation. I
find it odd that such a simple, in fact the simplest, photon interaction
requires such a heavyweight description at the 'fundamental' level. One
would think such a description would be a simple basic function of QM.
But I digress....
Its quite interesting that typically (that is in a lownoise situation)
we detect single photons when the detector has been exposed to an
adequate flux of EM radiation such as to accumulate about a photonsworth
of energy. This is entirely consistent with photons actually being EM
waves. The fact that we emit and absorb precisely a photonsworth says
more about the quantised emitters and detectors (exemplified by atoms)
than of the quantum nature (if any) of the EM wave itself.
" IMHO the dichotomy derives in part from ignoring the reality of
detectors. Photon detectors are typically large massive (ie contain
much energy) and thus highly localised particles like atoms. This leads
people to imagine photons as little bullets that hit equally tiny
atoms, instead of vast waves (of wavelengths thousands of times larger
than the emitting/absorbing atom) interacting with tiny atoms. This
seems to be intuitively less stressful to imagine, suppressing the QM
fact that a particle localised precisely at a point, will have infinite
momentum. "
Quantum Paradox of a SelfInterference of a Photon in VLBI:
http://groupsbeta.google.com/group/sci.physics.research/msg/f891e2033b2b5ec2?dmode=source
Please comments
Really, what "most people" understand by the term "photon"
isn't necessarily going to be of much help.
The only sensible definition I know of is that a photon is
a single excitation of a quantized EM field mode. These
modes are generally described by a wiggly "wavelike" functions;
and hence behave like waves, but the quantum excitations
within them are discrete. Note that you can make superpositions
of different mode functions, and superpositions of the excitations
within these.
The main advantage of this model is that people actually use it
to get answers; and they get ones that agree with experiment.
I suggest you search the achives of this group for the various
"what is a photon" discussions.

+
Dr. Paul Kinsler
Blackett Laboratory (QOLS) (ph) +442075947520 (fax) 47714
Imperial College London, Dr.Paul...@physics.org
SW7 2BW, United Kingdom. http://www.qols.ph.ic.ac.uk/~kinsle/
Of course the "famous" one from here is all condensed at,
http://math.ucr.edu/home/baez/photon/schmoton.htm
Hmm... I am not sure what you mean by "this" exactly. Photons as
wavicles?
 1) For any give emission of a photon by an atom we can locally obtain
 the direction of emission from the recoil of the emitting atom (to some
 level of accuracy).
However, this limits the energy of a photon to that range which would
recoil just one atom. Can a lower energy photon recoil just one atom?
 2) This concludes the description as far as the emission is concerned.

 3) Similarly for any given absorption (why is this not spelled
 absorbtion to go with absorb?) we can locally obtain the direction the
 photon came from by measuring the recoil.
Same argument. And a noticable recoil of an atom would maybe require a
photon in the range of going from soft to hard photons.
 4) This concludes the description as far as absorption is concerned.

 5) We note that (1) is the timereversed description of (3).

 Following the ageold technique of physicists we model this by sweeping
 as much complexity under the carpet and combining the two pictures by
 postulating an unobserved particle with the properties of a photon. Its
 a transmitted chunk of energymomentumspin. Much like a neutrino....
Yes, only a boson instead of a fermion.
 Unfortunately this description is just that, a description, and isn't
 much help in predicting. Predictive techniques have been developed..

 Even worse I suspect that a QM description of a single photon with a
 reasonably welldefined momentum (ie direction) would be somewhat non
 trivial to set up. A complex function of an infinity of states with
 expectation one, whether its done in particle or wave formulation. I
 find it odd that such a simple, in fact the simplest, photon interaction
 requires such a heavyweight description at the 'fundamental' level. One
 would think such a description would be a simple basic function of QM.
 But I digress....
In the relativistic medium picture, it is even more complex. Photons in
QED looks like a simplification compared to that. ;) Photons in the
relativistic medium picture have to have a mix of both electroweak and
strong in them. With low energy photons not have very much of the
strong force mixed in but high energy photons should have a higher
degree of the strong force mixed in. Seems logical since high energy
photons can produce hadrons. Charge is charge. We just happen to have
different kinds of charge. It's a mechanical process even if it is
quantum *mechanical*.
 Its quite interesting that typically (that is in a lownoise situation)
 we detect single photons when the detector has been exposed to an
 adequate flux of EM radiation such as to accumulate about a photonsworth
 of energy. This is entirely consistent with photons actually being EM
 waves. The fact that we emit and absorb precisely a photonsworth says
 more about the quantised emitters and detectors (exemplified by atoms)
 than of the quantum nature (if any) of the EM wave itself.
Yes, it is easy to take the viewpoint that the quantum nature of photons
is from the emitters and detectors. For me that seems to go against the
Standard Model where all the elementary particles are excitations of the
quantum "vacuum". This indicates to me that spacetime and matter are
"composed" of the same stuff. Just configured differently. If that is
the case, then hbar has to be a "vacuum" process just like c. This
means a free space electromagnetic field can be quantized. IMHO, it is.
There is very little doubt in my mind that both spacetime and matter
are quantized and composed of the same "stuff". If you haven't read it
yet, I highly suggest Volovik's "The Universe in a Helium Droplet". He
concludes with the proposal that all physics is emergent from analogies
of superfluid helium studies with the quantum "vacuum" except for hbar.
Hbar remains fundamental. For now. I can see that what is might be
more fundamental than hbar is a fractal of the sqrt(hbar). The key is
the the geometrical configuration of the interactions of the fundamental
entities that make all of this. Is string theory the answer to the hbar
question? Maybe.
> 1) For any give emission of a photon by an atom we can locally obtain
> the direction of emission from the recoil of the emitting atom (to some
> level of accuracy).
>
>However, this limits the energy of a photon to that range which would
>recoil just one atom. Can a lower energy photon recoil just one atom?
No, and interestingly nor can a higher energy photon.
The range of energies of absorbable photons is as narrow as the range of
emitted photons. This is because, in effect (and actually)
absorbtion/emission is a matched tuned/resonant system.
Of course one can brutally strip electrons from atoms by applying an
adequately large electric field, but this is many orders of magnitude
higher fields than pertain to the resonant system.
> 3) Similarly for any given absorption (why is this not spelled
> absorbtion to go with absorb?) we can locally obtain the direction the
> photon came from by measuring the recoil.
>
>Same argument. And a noticable recoil of an atom would maybe require a
>photon in the range of going from soft to hard photons.
Maybe. I did once ask for , and IIRC offered a simple analysis for, the
recoil from a cold emitting H atom. It was indeed rather small.
> Unfortunately this description is just that, a description, and isn't
> much help in predicting. Predictive techniques have been developed..
>
> Even worse I suspect that a QM description of a single photon with a
> reasonably welldefined momentum (ie direction) would be somewhat non
> trivial to set up. A complex function of an infinity of states with
> expectation one, whether its done in particle or wave formulation. I
> find it odd that such a simple, in fact the simplest, photon interaction
> requires such a heavyweight description at the 'fundamental' level. One
> would think such a description would be a simple basic function of QM.
> But I digress....
>
>In the relativistic medium picture, it is even more complex. Photons in
>QED looks like a simplification compared to that. ;)
Somehow this doesn't surprise me at all.
>Photons in the
>relativistic medium picture have to have a mix of both electroweak and
>strong in them.
Ugh!
>With low energy photons not have very much of the
>strong force mixed in but high energy photons should have a higher
>degree of the strong force mixed in. Seems logical since high energy
>photons can produce hadrons. Charge is charge. We just happen to have
>different kinds of charge. It's a mechanical process even if it is
>quantum *mechanical*.
Waves are perfectly mechanical objects.
I suspect particle waves are not trivial though,
else it would be well understood by now.
>Yes, it is easy to take the viewpoint that the quantum nature of photons
>is from the emitters and detectors. For me that seems to go against the
>Standard Model where all the elementary particles are excitations of the
>quantum "vacuum".
The standard model is a descriptor.
A potent and powerful descriptor.
But it uses the particulate description for all the (very good) reasons
I gave earlier.
>This indicates to me that spacetime and matter are
>"composed" of the same stuff. Just configured differently. If that is
>the case, then hbar has to be a "vacuum" process just like c. This
>means a free space electromagnetic field can be quantized. IMHO, it is.
Maybe. However I don't have any serious evidence to support that, whilst
there is reams of evidence for photons being entirely wavelike. Massive
particles are clearly different and have something 'extra', ie rest
mass. This appears to result in an inability to disperse. One
instinctively reaches for a solitonlike description for these, hence my
longstanding (if shallow) interest in these. One can imagine that a
solitonlike description would give an object where if it disperses
spatially it condenses temporally and viceversa. That could neatly
express h in an elemental way.
>There is very little doubt in my mind that both spacetime and matter
>are quantized and composed of the same "stuff".
I would not disagree. In fact I would go further and say that matter
makes spacetime, the two are identical.
>If you haven't read it
>yet, I highly suggest Volovik's "The Universe in a Helium Droplet". He
>concludes with the proposal that all physics is emergent from analogies
>of superfluid helium studies with the quantum "vacuum" except for hbar.
>Hbar remains fundamental.
I'm currently struggling through the koran. Its very heavy weather but
the most shocking religious document I have ever read. I may be some
time in completing it.
>For now. I can see that what is might be
>more fundamental than hbar is a fractal of the sqrt(hbar). The key is
>the the geometrical configuration of the interactions of the fundamental
>entities that make all of this. Is string theory the answer to the hbar
>question?
Hey!
You aren't allowed random cranky speculation,
that's my job.
I for one and I think others admire the research
to describe a photon between the times it's emitted
and absorbed. It's very difficult to test that
photon structure experimentally, but it would be neat
if a photon structure was imposed upon a gfield
rationally and GR's light deflection and attenuation
predictions were to be found within some common
Maxwell field, as well as GR, to lead to a formalized
unification of EM and GR.
Recently, Jay Yablon, and Fred Diether have pointed
out an AE idea about the *strength* of Equations,
specifically AE's book, "Meaning of Relativity",
in the section on Nonsymmetric Field (pgs 133139
are dedicated to that topic).
I'll quote from page, 139,
"It is surprising that the gravitational equations
for empty space determine their field just as
strongly as do Maxwell's equations in the case of
the electromagnetic field."
AE is quite specific about equation strength, and
he provides the formula and the quantity "z" to
designate that.
In my understanding if the Maxwell's z and the GR's
z are equal, then they those equations are compatible,
in the sense the can be intermixed, I think a
mathematical physicts may provide a better explanation,
and invited.
So there is a good reason the EM structure of a
photon is compatible relationally with a gfield.
Hence the photon structure can be subject to
GR effects, and is therefore able to be examined,
from a theortical perspective as a test.
Another *benchmark* test for a photon test relates
to SR and Doppler Effects.
In that case we set up a gedanken with a photon
bouncing between relatively moving mirrors.
Suppose mirror A and B are receding, and a
photon is pingponging between the two, well
the photon will be Dopplershifted by each
reflection, I think that's apparent, as measured
by someone at either mirror.
The 2 mirrors plus the photon are a "closed"
system and therefore a conserved system, Ok?
Stop here
Ken S. Tucker
I'm unsure where you see a problem here.
Surely total energy momentum of the whole system is conserved.
The mechanism is simply a device for converting lightmomentum into
mirrormomentum.
Hi OZ et al.
> I'm unsure where you see a problem here.
I'll explain *my* problem below...
> Surely total energy momentum of the whole system is conserved.
Yes, no doubt. (but don't call me Surely:)
> The mechanism is simply a device for converting lightmomentum into
> mirrormomentum.
Sorry, no. Imagine two stationary mirrors with a
relatively large mass, and 100% reflective efficency
then ideally a photon will bounce back and forth
virtually indefinitely without imparting momentum to
the mirrors, at least take that as the gedanken basis.
In that gedanken, everything is idealistically clear.
Let me vary that gedanken by having the mirrors
move apart such that they have a *constant* relative
Kinetic energy.
Now I'm sure everyone (who had a speeding ticket)
understands the Doppler shift to a radar beam when
reflected from a relatively moving object.
Well the reflected *photon* is redshifted by
Doppler (not momentum exchange).
Now that's a closed system, nothing in, nothing out,
so we need to conserve the energymomentum of the
system.
In the absence of the photon, it's easy to conserve
the kinetic energy of the mirrors, it remains constant.
When the photon is introduced, we find it's red
shifted by each reflection, (Doppler radar), so
that photon is loosing energy, by Plancks E=h*f.
Stop again...
Regards
Ken S. Tucker
> Sorry, no. Imagine two stationary mirrors with a
> relatively large mass, and 100% reflective efficency
> then ideally a photon will bounce back and forth
> virtually indefinitely without imparting momentum to
> the mirrors, at least take that as the gedanken basis.
> In that gedanken, everything is idealistically clear.
>
> Let me vary that gedanken by having the mirrors
> move apart such that they have a *constant* relative
> Kinetic energy.
> Now I'm sure everyone (who had a speeding ticket)
> understands the Doppler shift to a radar beam when
> reflected from a relatively moving object.
> Well the reflected *photon* is redshifted by
> Doppler (not momentum exchange).
>
> Now that's a closed system, nothing in, nothing out,
> so we need to conserve the energymomentum of the
> system.
> In the absence of the photon, it's easy to conserve
> the kinetic energy of the mirrors, it remains constant.
>
> When the photon is introduced, we find it's red
> shifted by each reflection, (Doppler radar), so
> that photon is loosing energy, by Plancks E=h*f.
> Stop again...
In the presence of infinitely massive objects
(or equivalently, ignoring O(1/m))
the law of energymomentum conservation doesn't hold.
Of if you prefer:
it does hold with all missing energymomentum
being absorbed by the massive object.
An object with infinite mass
can absorb any finite amount of energy and momentum
without changing velocity.
Best,
Jan
Robin,
I used to have the same problem with the energy of the photon. I have
solved it, to my satisfaction. My problem was with the "fact" that a
radio photon of, say, a 100km wavelength has less energy than a light
photon just a few hundred nanometers in wavelength. It appears to be a
reversed correlation. Lets try with the photon as a power, i.e. lets
consider the photon as a quantum of action as a power. It is after all
prepackaged in a fixed amount of time, the period, that specifically
determines how long it will take to deliver the said quantum of action.
This is demonstrated in the photon absorption by an oscillator. The
radio antenna will have to waitfeel that the whole 100km of the radio
wave go by before having absorbed the energy of each radio photon.
This picture does make the photonenergy understandable but does not
solve my problem since this way, all photons have the same quantum of
action; their only difference resides in the time package they come with
and that determines how quickly this quantum is delivered. But at least,
I don't have a reversed correlation anymore; a longer photon takes a
longer time to deliver its quantum of action and is logically less
powerful.
Problems in understanding quantum mechanics, I believe, come from not
understanding that the nature of the photon appears to change between a
prepackaged power potentiality (photon flying by) and the integrated
event that constitute the absorption. In fact, the absorption IS the
actual event, which takes a certain amount of time to happen. The
signature of this power, or work over time, is dismissed/dismissed and
integrated as the total and final energy, or work done.
So, to me, the photon is a quantum of action prepackaged in a certain
amount of time, a power, which will interact only with oscillator tuned
to receiving this quantum of action, exactly at the same rate as it is
meant to be delivered. A power that induces and allows the absorption
event to happen only in a certain amount of time. ENERGY is just about
us tallying up the final integrated result. Big difference here!
MarcelM. LeBel
> If we consider emr which arises from a specific quantum of
> energy, ala photon, it seems to me that this emr carries
> with it either the whole amount of energy and momentum, or
> the probability of this energy and momentum. But when the
> emr is mixed with other emr the resulting patterns of
> energy deposition depend on all the relevant sources
> and how they interfere at each point which could absorb
> them.
>
> We observe that there is a direct relationship between the
> frequency spectrum of the emr and the distribution of
> energies in the quanta it deposits. A sinewave leads to
> only one energy level. A single arbitrary shaped pulse
> creates a particular and easily predicted probability
> distribution for the relationship between quanta energy
> levels and the number of such quanta deposited.
>
> So I think the quanta which may have given rise to the emr
> do not necessarily have anything to do directly with the
> quanta which are deposited.
> .....
Robin,
MarcelM. LeBel
 le...@muontailpig.com remove particle from address
note to moderator: sent previously without proper return address
correction. My mistake.
Ok Jan, but we, IMO can't attribute Doppler Effect
to transfer of energymomentum to the reflecting
surface. If we were to council that idea, then
the faster something is moving from the "Doppler
radar ranging source, the greater it would absorb
photon energymomentum...
I'll try to define the terms in math, beginning
with an energymomentum invariant denoted "p".
"p" is also constant for any system of particles,
provided no energy gets in or out, relative to all
FoR's (Frames of Reference).
>From a contravariant 4velocity U^u and covariant
U_u we generate
p^u=p*U^u and p_u=p*U_u generally.
For surety, I'll adopt the metric in this case
g00...g33=1 and U_i =0 {i=1,2,3}
and complies with ds^2=g_uv dx^u dx^v,
and Minkowski's
ds^2 = dt^2  dr^2.
Using the condition U_i=0 provides an
important simplification in relativity,
because
p_i=0 =(p*U_i=0) hence,
p_0 == rest energy, (p_i vanishes).
Now, in any lab frame one defines Plancks
constant "h" by the product, ergs*seconds,
where the erg's (mass) is at rest in the
Lab frame, hence p_0 is Lab ergs. Since
"h" has proven invariant it follows,
h = N*p_0*U^0 ,
where U^0 is seconds in the Lab frame,
and N is an arbituary number ~ 6.625*10^27,
and is invriant.
The measurements of mass and time in the
Lab frame are not invariant, since they
are true to only that Lab. Another Lab'
moving past Lab will disagree with the
measures of p_0 and U^0, and will obtain
p'_0 and U'_0 for those relative quantities
but will agree that,
h = p'_0*U'^0
is invariant.
I'll stop here pending replies...
Regards
Ken S. Tucker