zaybu wrote:

twistor59 wrote:
But, if you read the paragraph carefully:

You could then, in principle, compute a modified propagator - an amplitude for propagation through glass. In this propagator, the photon would have a mass. It would be off-shell.

Are we talking about the same paper, the Zhang paper at http://arxiv.org/PS_cache/arxiv/pdf/110 ... 5783v3.pdf , ???

If we are, I can't find that sentence, "In this propagator, the photon would have a mass." Could you direct me to the page and paragraph? ( I did a search with MS-word, and that sentence is not in that paper.)

zaybu wrote:
As that paper maintains, off-shell is from the controversy that p = ℏk/n (Abraham) OR p = n ℏk (Minkowski). It has nothing to do with the speed of a photon, it doesn't slow down, or its mass, it doesn't acquire any mass.

twistor59 wrote:

small in magnitude for opaque media
large in magnitude for transparent media
have a phase behaviour which is the same as you'd get by giving the photon a mass whilst it was in the medium

Never heard of such explanation and I don't think it's right. It's just based on your Feynman's speculation.

twistor59 wrote:

zaybu wrote:

Never heard of such explanation and I don't think it's right. It's just based on your Feynman's speculation.

FIFY

zaybu wrote:

twistor59 wrote:

zaybu wrote:

Never heard of such explanation and I don't think it's right. It's just based on your Feynman's speculation.

FIFY

Feynman would not be proud.

twistor59 wrote:

zaybu wrote:

twistor59 wrote:


FIFY

Feynman would not be proud.

Well, Feynman was a fairly modest person, but I'm sure he would feel just a little bit proud, secretly, that he could now use his models of elementary processes to explain macroscopic phenomena such as refraction.

zaybu wrote:

twistor59 wrote:

zaybu wrote:

Feynman would not be proud.

Well, Feynman was a fairly modest person, but I'm sure he would feel just a little bit proud, secretly, that he could now use his models of elementary processes to explain macroscopic phenomena such as refraction.

Of course, he would, as the Zhang paper is one of many examples. However, he would not be proud of your speculation. (Photon slowing down, acquiring mass, )

It is an effective propagator designed to compute the amplitude PhotonIntoMedium -> PhotonOutOfMedium

As strict Copenhagenists, the nature and behaviour of the photon while in the medium, we can't determine, all we can do is add up all the possibilities according to the rules. This will result in a propagation amplitude which will be:

small in magnitude for opaque media
large in magnitude for transparent media
have a phase behaviour which is the same as you'd get by giving the photon a mass whilst it was in the medium

twistor59 wrote:

zaybu wrote:

twistor59 wrote:

Well, Feynman was a fairly modest person, but I'm sure he would feel just a little bit proud, secretly, that he could now use his models of elementary processes to explain macroscopic phenomena such as refraction.

Of course, he would, as the Zhang paper is one of many examples. However, he would not be proud of your speculation. (Photon slowing down, acquiring mass, )

You seem to be having difficulty understanding the terminology and concepts. I'll repeat my entire paragraph just so that the correct context remains:

It is an effective propagator designed to compute the amplitude PhotonIntoMedium -> PhotonOutOfMedium

As strict Copenhagenists, the nature and behaviour of the photon while in the medium, we can't determine, all we can do is add up all the possibilities according to the rules. This will result in a propagation amplitude which will be:

small in magnitude for opaque media
large in magnitude for transparent media
have a phase behaviour which is the same as you'd get by giving the photon a mass whilst it was in the medium

Do you not understand the highlighted phrases ?

On the other hand, if a photon has an energy beyond the phonon spectrum, then while it can still cause a disturbance of the lattice ions, the solid cannot sustain this vibration, because the phonon mode isn't available. This is similar to trying to oscillate something at a different frequency than the resonance frequency. So the lattice does not absorb this photon and it is re-emitted but with a very slight delay. This, naively, is the origin of the apparent slowdown of the light speed in the material. The emitted photon may encounter other lattice ions as it makes its way through the material and this accumulate the delay.

zaybu wrote:

twistor59 wrote:

You seem to be having difficulty understanding the terminology and concepts. I'll repeat my entire paragraph just so that the correct context remains:

It is an effective propagator designed to compute the amplitude PhotonIntoMedium -> PhotonOutOfMedium

As strict Copenhagenists, the nature and behaviour of the photon while in the medium, we can't determine, all we can do is add up all the possibilities according to the rules. This will result in a propagation amplitude which will be:

small in magnitude for opaque media
large in magnitude for transparent media
have a phase behaviour which is the same as you'd get by giving the photon a mass whilst it was in the medium

Do you not understand the highlighted phrases ?

Yes, and in no way does it support your claim.