"Creighton Hogg" <wchogg@hep.wisc.edu> wrote in message
news:Pine.LNX.4.44.0405261303230.20192-100000@azalea.hep.wisc.edu...

On Wed, 26 May 2004, Ed Keane III wrote:

"Creighton Hogg" <wchogg@hep.wisc.edu> wrote in message
news:Pine.LNX.4.44.0405261042070.20192-100000@azalea.hep.wisc.edu...

On Wed, 26 May 2004, Ed Keane III wrote:

"Bjoern Feuerbacher" <feuerbac@thphys.uni-heidelberg.de> wrote in

message

news:c91su5$e59$2@news.urz.uni-heidelberg.de...

Ray Price wrote:

This may sound like a stupid question, but please bear with me

here.

At the most basic level, let's say nothing existed in the

universe

except

for two electrons (I know you will probably say there is no

balance

here,

but this is just theoretical). What is it that repels these two

particles

away from each other? Is there something smaller than these

particles

that

is unseen and providing some kind of communication between the

two?

Is

there something inside the particles providing communication? I

guess

my

real question is... how do they even know of each others

existence?

Ever heard of (virtual) photons?

Try reading this:
<http://www.faqs.org/faqs/physics-faq/part4/> (scroll down to item

32)

If there are only two electrons and nothing else in the universe
would the concept of repulsion mean anything? The relative
position of the two would not change. There is no reference to
compare time with. Is there even such thing as a rate of virtual
photon exchange that could be said to change with time, much
less be measured?

QED isn't conformally invariant, scale matters even if you don't have

a

convenient way to measure it. The electrons will bremstrahlung (I bet

I

botched the spelling again) because of the acceleration. The
bremstrahlung spectrum will change over time as the acceleration
experienced by the electrons changes.

I do not think the electrical force between electrons would cause
bremsstrahlung (not in MS spellcheck) unless they were colliding
at high energy because it is not caused by weak accelerations.
However that assumption seems to rely on some concept of scale.
How does scale matter in the case of two electrons in QED?

It doesn't even matter if the radiation of the charges doesn't happen at
small accelerations, although I believe it does. The couloumb
repulsion is related to the distance between charges, and if your claim
that scale has does not matter in this case is true then it's perfectly
okay for me to choose the electrons to be arbitrarily close together,
resulting in an arbitrarily high acceleration. My previous argument would
still hold. The dynamics of the system would change as the electrons move
apart and thus the distance between them matters.

I think that a change in direction is neccesary for bremsstrahlung
radiation.
I do not think that the dynamics of the system is scale, or distance (same
thing?), dependant. But I don't know.