Steve McDaniel wrote:
In "Fundamentals of Physics" by Halliday
and Resnick 1974 edition [my old physics textbook from college] page
710 states "The act of light emission by a single atom [which I thought was a
photon] takes, in a typical case, about 10^-8 seconds and the emitted
light is properly described as a wavetrain rather than as a wave. For
emission times such as these the wavetrains are a few meters long."
"Interference effects from ordinary light sources may be produced
...[The text then proceeds to describe a single slit follow by a
double slit] The diffracted beams [from the double slit] thus
represent the same population of wavetrains and are coherent with
respect to each other."
Is the above text refering to a photon as a wavetrain?
Yes, it looks indeed like that.
I had assumed
that a wavetrain is a concatenation of photons (such as through
stimulated emission or antenna excitation) that are locally coherent
but may drift as more photons are concatenated resulting in
incoherence in the same wavetrain. Is that view correct?
I think both views can be correct. A wavetrain may "contain" one or
more photons.
How does one split a wavetrain (a concatenated photon stream?) into
two paths such as the double slits and provide cloned wavetrains to
both paths?
If the wavetrain is a plane wave, the splitting happens by itself -
parts of the wave arrive at the one slits and other parts at the other.
How does splitting or cloning effect the photons (if
there is such a thing) involved in the wavetrains?
One can argue that the photon goes through both slits at once.
Have you ever read Feynman's explanations for the double slit
experiment? (in his lectures on physics, volume 3, and also in the
popular science book about QED, IIRC)
Are the streams of photons split in two?
In a sense, yes. Each photon has a probability amplitude to go through
one slit, and a probability amplitude to go through the other. As
mentioned above, one could say that it goes through both at once.
Do multiple quanta of
photons occupy the same space (i.e. the variable n in plancks equation
E=nhv).
Could happen, yes.
Is a wavetrain then actually a train of concatenated
overlapping photon sets?
Depends on the wavetrain, I would say...
Or does n describe the harmonic number or
energy level of an oscillating self supporting electromagetic field
i.e. a photon that moves at the speed of light?
No, n is the number of photons. According to QED, photons are
excitations of the electromagnetic field - and that field can be
described as infinitely many coupled harmonic oscillators. That's why
the same formula applies here than for the energy levels of a harmonic
oscillator.
Can I subtract quanta
from the photon and essentially clone the photon at lower energy
levels?
The photon *is* a "quantum". Subtracting quanta from it makes no sense.
Is each photon or quanta thereof directed to one slit or the other
with a certain probability according to spatial orientation?
No. See above.
Is there really a quanta (i.e. the variable n in plancks equation
E=nhv) involved with photons or is that simply an atomic effect and
all bets are off once the photon is emitted?
Well, QED predicts that photons exist. QED is also the best tested
theory in physic ever, where several theoretical predictions agree with
the experimental tests with ten significant digits or better, and which
has never been disproven so far. I would count that as strong evidence
that photons indeed exist, wouldn't you?
Is there really such a thing as photons?
Yes.
See for example THE PHOTON FACT OR FICTION? By BERT SCHREIBER.
What's this?
Last of all. How in the world can the emission of light take so long
in an atom (several meters worth of light as suggest in the above
reference)
10^(-8) seconds is long for you???
and how can the photons or wavetrains be so much larger
that the atoms from which they are emitted or the wavelengths they
correspond to?
Has it ever occured to you that long radio waves are *also* much longer
than the antennas which emit them usually?
What is so strange about that is that the small energy
drops would seem to take longer to occur/emit than the larger energy
drops.
Why do you think so???
I seek clarification not confusion so please respond accordingly.
I hope I could help a bit...
You could also try looking here:
<http://math.ucr.edu/home/baez/photon/schmoton.htm>
Bye,
Bjoern
.
