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Old August 13th 03, 01:19 PM
Aleksandr Timofeev
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Default Gravitation and Maxwell's Electrodynamics, BOUNDARY CONDITIONS

\(formerly\)" dlzc1.cox@net wrote in message news:rbWZa.9683$2g.438@fed1read05...
Dear Aleksandr Timofeev:

"Aleksandr Timofeev" wrote in message
om...
\(formerly\)" dlzc1.cox@net wrote in message

news:4EWYa.7556$2g.401@fed1read05...
Dear Sergey Karavashkin:

"Sergey Karavashkin" wrote in message
m...
Dear David,

Until you are trying to find a phenomenon in which wave physics
'doesn't work', and another phenomenon which is at least so-so
described by photon theory, you will be unable to grasp the essence
of issues.

[snip]

Thus, we are convinced once again,
that the so-called orthodox science is religion.


He has made no substantive comment in the post to which I replied.
Certainly nothing except his opinions. And he left not one shred of my
last post to him, to continue a dialog.

So if you wish to quit your posturing, we can continue *our* discussions.

You (and Sergey) wish to continue describing the behaviours of light with
the class of equations that describe gestalt behaviours. This is a
wonderful and useful idea. It will help you get the job done, perhaps even
in your lifetime.

It does not alter the inescapable fact that the gestalt is made of quantum
particles, that conform to producing, among other things, the
photoelectric effect. I have heard many people *claim* that waves can
describe the photoelectic effect, but they always seem to fall short. They
never seem to get past "resonance" in fact.

You go ahead and believe that light is waves-only. Reality doesn't care
one whit what you or I believe.

If our beliefs are held up to the light of experiment though, and are shown
to be limited in their scope, and we continue to claim that they still
describe all of nature...


" What, then, is a photon's wave-function?

I'm taking it to be a solution of Maxwell's equations,
either described using the vector potential in some fixed
gauge, or perhaps even better for the present purposes,
using the electric and magnetic fields. "
sci.physics.research John Baez

http://groups.google.com/groups?selm...pravda.ucr.edu
================================================== ===============
From: john baez )
Subject: photon wave-functions?
Newsgroups: sci.physics.research
Date: 1999/01/27


In article ,
(Greg Weeks) wrote:
In the discussion single-photon wavetrains, it seems to be
generally assumed that the photon has a wave-function.
Even in free field theory, I don't believe this is true.


Education is a process of telling a carefully chosen
sequence of lies in which the amount of deliberate
deception gradually tends towards zero. There is a limit
to how much truth someone can absorb all at once without
their brain turning to jelly!

Oz - or whoever originally asked the question - seems to
be wondering something like "what's the shape of the
wavefunction of a photon of a given energy?" Of course
they're not phrasing it that way, but that's my desperate
attempt to translate it into something I can understand.

Now you're right, it's a bit of a pity that they chose
a *photon* as the particle to ask about in this question.
Massless particles are a

"the political nuisances of the day"

because the Newton-Wigner localization breaks down.
Gauge bosons are a nuisance
because it's harder to separate out the physical degrees
of freedom in a gauge theory. So even *ignoring* the extra
subtleties when we take interactions into account and drop
the pleasant fictions of free field theory and Fock space,
we have some serious issues to deal with in a complete
answer to this question!

But if someone asks the question "what's the shape of
the wavefunction of a photon of a given energy?" and you
start talking to them about Newton-Wigner localization,
gauge-invariance, and Fock space, their brain is going to
turn to jelly! They're going to walk away in a daze
having learned nothing.
They'll probably be shocked that such a simple
question elicited such a complicated bunch of mumbo-jumbo.
They may become politicians and cut funding for physics.

So you have to tell them something helpful even if it's
oversimplified.

First and foremost, it seems to me, you have to disabuse
of them of the assumption that the wavefunction of
a particle has some fixed "wavetrain with finitely many
wiggles" shape that depends solely on the energy of the
particle. When one starts out learning physics, one tends
to think of a particle as a little tennis ball or something,
perhaps with some wiggly waves thrown in for good measure.
The idea that it's just a "field mode" doesn't come easily!
Usually one absorbs this slowly and painfully by solving
Schrodinger's equation with all sorts of different boundary
conditions and potentials, learning all sorts of different
orthonormal bases for the space of states, and eventually
realizing that the choice of basis is just a matter of
convenience. The idea that a particle is just a solution of
a partial differential equation and that there are *lots*
of solutions having the same expectation value of energy,
or even the same eigenvalue - that doesn't come easily!
So, somehow you have to broach these issues.

Thus I'm reluctant to talk about the issues you're raising
now. They're too fancy for this conversation. I'll just
whisper to you the approach I'm implicitly taking towards
this question:

What, then, is a photon's wave-function?


I'm taking it to be a solution of Maxwell's equations,
either described using the vector potential in some fixed
gauge, or perhaps even better for the present purposes,
using the electric and magnetic fields. I bet people who
do quantum optics do something like this when they talk about
the wavefunction of a photon, and I don't think it's so bad,
despite the objections you note.
================================================== ===============


I don't think I am the one peddling religion, Aleksandr. Bullsh*t seems to
be produced on all continents.


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