Re: QFT question

"Guy Gordon" <gordon@xxxxxxxxxxxxxxxxxxxxx> wrote in message
news:778791d42f6hsn2k3al810gan2u3do3dpe@xxxxxxxxxx
| Bjoern Feuerbacher <bjoern.feuerbacher@xxxxxxxxxxxxxxxxxxxxx> wrote:
|
| >Guy Gordon wrote:
| >> Are virtual photons the same as the EM field?
| >>
| >> By that I mean, do they fulfill all the EM field such that one
could say that
| >> virtual photons *are* the EM field, or that the EM field is made up
of virtual
| >> photons?
| >
| >Photons, virtual or real, are excitations of the EM field.
| >
| I would agree with that statement. But I'm trying to understand
Richard
| Feynman's explanation of QED in "QED The Strange Theory of Light and
Mater".

Except that the statement is wrong. Photons are quanta of the EM field.
They are "excitations" of the quantum "vacuum".

| In Chapter 3 he seems to be saying that there is no EM field. I think
most
| people would say that the interaction of two electrons are "mediated"
by virtual
| photons. Feynman seems to be saying "No, there's nothing *but* the
virtual
| photons."

If photons are quanta of the EM field, then how could there be no EM
field?

| He also says that a 'virtual' photon is nothing but a photon that does
not
| appear in the beginning and end states of an interaction.

Correct in the strict sense of "virtual".

FrediFizzx

.

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