On Thu, 16 Aug 2007, Anonymous. wrote:

> "John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
> > All electromagnetic radiation is the same. It's all quantized.
>
> Is there any experimental evidence for that?

Sure. Some of it is indirect. There are many systems where the energy
states are not discrete, where the electrons occupy a continuum of energy
levels, and are not limited to discrete jumps. However, the frequency of
radiation emitted is still proportional to the change in energy.
Quantisation of EM radiation has nothing to do with discrete atomic energy
levels - that just gives you a discrete line spectrum instead of a
(quantised) continuous spectrum.

The spectrum of continuous spectra emitted by hot bodies and cold bodies
being the Planck spectrum is a good sign that low and high frequencies are
identically quantised. 21cm radiation from an atomic source looks the same
to a detector as 21cm radiation from an antenna. The Hanbury Brown-Twiss
intensity interferometer works identically for RF and optical frequencies.

It's worth keeping three things in mind about all this:

(a) Photons, as described by our best description of them so far, QED, are
_not_ little billiard balls. To call them "particles" is misleading, they
have very little in common with our classical idea of "particle". The same
equations - the Maxwell equations - describe the behaviour of photons and
of classical EM radiation.

(b) There is no experimental evidence _against_ RF EM radiation being
quantised. The high-photon-number limit of QED gives us the observed
behaviour.

(c) What kind of theory can explain the existence of a "magic wavelength",
above which you get quantisation, and below which you don't? A few items
that require explanation: why do waves from both atomic sources and
antennas behave the same?, since the observed wavelength of the source
depends on the motion of the source relative to the observer, how does
this affect the magic cut-off wavelength?, why are RF blackbody
spectra Planckian?, and why is (most of) the behaviour of quantised EM
radiation described by the same Maxwell equations as unquantised EM
radiation, while the equations that describe the behaviour of quantised EM
also describe all of the observable behaviour of low-frequency EM
radiation?

--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
E-prints: http://eprint.uq.edu.au/view/person/Nie ... mo_A..html
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html

On Thu, 16 Aug 2007 20:42:05 +0100, Anonymous. wrote:
> "Andy Resnick" <andy.resnick@op.case.edu> wrote in message
> news:fa28g4$d1f$1@eeyore.INS.cwru.edu...
>> Anonymous. wrote:
>>> "John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in
>>> message news:nir8c3hcagq7rcnilfshorqqmrhpq0mhl7@4ax.com...
>>>>All electromagnetic radiation is the same. It's all quantized.
>>> Is there any experimental evidence for that?
>> Cavity QED experiments performed using microwaves, among other
>> experiments.
>
> Microwaves cover the frequencies of atomic effects, such as the
> hydrogen line, where one might expect quantum effects to appear.
>
> What about in the medium wave band, say, from 500kHz to
> 1500 kHz.....how are photons detected at those frequencies
> and disambiguated from continuous waves?

I think that the disambiguation happens when it's detected.
I remember reading somewhere once about the "quantum wave function",
which goes in all directions, but when it's detected, the QWF
collapses and the whole photon lands in the receiver, whether it
be 40-meter antenna or retina.

Cheers!
Rich

Anonymous. wrote:
> "Andy Resnick" <andy.resnick@op.case.edu> wrote in message
> news:fa28g4$d1f$1@eeyore.INS.cwru.edu...
>
>>Anonymous. wrote:
>>
>>>"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in
>>>message news:nir8c3hcagq7rcnilfshorqqmrhpq0mhl7@4ax.com...
>>>
>>>>All electromagnetic radiation is the same. It's all quantized.
>>>
>>>Is there any experimental evidence for that?
>>
>>Cavity QED experiments performed using microwaves, among other
>>experiments.
>
>
> Microwaves cover the frequencies of atomic effects, such as the
> hydrogen line, where one might expect quantum effects to appear.
>
> What about in the medium wave band, say, from 500kHz to
> 1500 kHz.....how are photons detected at those frequencies
> and disambiguated from continuous waves?

http://adsabs.harvard.edu/abs/1993AmJPh..61..545S

150 - 1000 MHz

The guy who did (Fred Seeley) this ran the undergraduate physics lab
while I was at grad school. It's incredibly simple and a great idea for
even a high-school project. The resonator is made from aluminized house
insulation panels, available at home improvement stores anywhere.

If you have a transmitter, you could do this yourself. It's a brilliant
experiment.

--
Andrew Resnick, Ph.D.
Department of Physiology and Biophysics
Case Western Reserve University