What are space-like and time-like virtual photons?

[Hans de Vries]

(Do you mean "an internal electron originates from the original electron but has a changed momentum {etc}"?)

Yes

I don't understand the physical meaning of "originates from the original electron".

"originates" how? where? and how/where does it de-originate?

It is the original electron field pertubated by the (alternating) photon field.
You have to think about the interaction of planewaves. The scattering zone
is considered wide enough to make this assumption valid.

And are you saying then that there is a physical internal electron for each internal electron line in each Feynman diagram (of which of course there are infinitely many) for the particular process?

In higher order diagrams there are electron and positron fields. Again, calling something
an electron and basing this on one of the quantization methods (electrons as
quantized excitations of the electron field) is something what you can do, or not do,
but it is not relevant for the end result. The pertubative series development is valid
with or without this interpretation of the individual terms.

And are you saying that there is a separate physical interference charge/current density between the original electron and each separate internal electron? And is there similarly a physical interference charge/current density between each pair of internal electrons?

No. The interaction is only with the photon which is connected to the interaction vertex.

Finally, what "incoming photon" (whose em field is to be negated)?

I didn't specify either an incoming or an outgoing photon in the interaction, and there doesn't have to be one!​

There has to be a photon, either incoming, outgoing or internal (if you are restricting
this to QED).


Regards, Hans

 

[Frame Dragger]

They call it a "virtual electron" instead...

I don't see how that helps in any way.

 

[Hans de Vries]

I don't see how that helps in any way.

Are you agreeing or objecting? Because I gave some reasons against
calling them "virtual particles" or worse, "space-like virtual particles"

Vacuum polarization could be associated with "virtual particles" if you
like, as long as the off-the-shell behavior is interpreted as the result
from interaction rather than from a propagator with an off-the-shell
mass.

Regards, Hans

 

[Frame Dragger]

Are you agreeing or objecting? Because I gave some reasons against
calling them "virtual particles" or worse, "space-like virtual particles"

Vacuum polarization could be associated with "virtual particles" if you
like, as long as the off-the-shell behavior is interpreted as the result
from interaction rather than from a propagator with an off-the-shell
mass.

Regards, Hans

I disagree with your definition of a virtual photon, but I agree that the term can be misleading... just not for the reasons you seem to think.

 

[Hans de Vries]

I disagree with your definition of a virtual photon, but I agree that the term can be misleading... just not for the reasons you seem to think.

I don't have a definition of what a "virtual photon" is...

-I have a definition of what goes on in a feynman diagram with an internal photon.
-I have a definition of what does not exist: virtual photons with a space-like imaginary mass.

Can you be more specific?

Regards, Hans

 

[Frame Dragger]

I don't have a definition of what a "virtual photon" is...

-I have a definition of what goes on in a feynman diagram with an internal photon.
-I have a definition of what does not exist: virtual photons with a space-like imaginary mass.

Can you be more specific?

Regards, Hans

I don't mean this as any kind of insult, but page 5 is too late to restart this discussion from basic principles. I think we're ultimately talking about the same physical (and transitional non-physical) processess, but we're not communicating that well. I think at this point You, myself, and Tiny-Tim are unlikely to change our views when they seem to be so entrenched. That, or against all odds, you're completely wrong, and I don't feel qualified or confident enough to show that. Tiny-Tim and you seem to be a better match; I'm no physicist, just a duffer.

 

[tupos]

An internal electron line originates from the original electron but has a changed
momentum

Regards, Hans

Nonsense. The definition of real electron

$$p^2 = -m_{R}^2$$ where $$m_{R}$$ is a real experimental mass.

There is no evidence to conclude that p^2 is equal to m^2 for internal electron line.

The same with photon, no evidence to say that k^2 = 0 for internal photon line.


Regards.

 

[Hans de Vries]

Nonsense. The definition of real electron

$$p^2 = -m_{R}^2$$ where $$m_{R}$$ is a real experimental mass.

There is no evidence to conclude that p^2 is equal to m^2 for internal electron line.

The same with photon, no evidence to say that k^2 = 0 for internal photon line.Regards.

Read my posts before shouting. Where did I ever make these statements which you
call nonsense? On the contrary, I'm protesting against descriptions which implicitly
make such assumptions, such as: "space-like virtual photons"

 

[tupos]

Hello Hans,

I didn't shout. Sorry if you get me wrong, I agree with you that there is no sense in space like and so on.

But you wrote and I commented it that "An internal electron line originates from the original electron but has a changed
momentum" you wrote it. I agree that nonsense is too strong word for this, maybe slightly incorrect is better

 

[Hans de Vries]

Hello Hans,

I didn't shout. Sorry if you get me wrong, I agree with you that there is no sense in space like and so on.

Hi, Tupos It's fine thank you.

But you wrote and I commented it that "An internal electron line originates from the original electron but has a changed
momentum" you wrote it. I agree that nonsense is too strong word for this, maybe slightly incorrect is better

Maybe that's a too popular description for you? A more technical description was given
here in this post: https://www.physicsforums.com/showpost.php?p=2574073&postcount=60

Regards, Hans

 

[tupos]

I know very well what is internal electron line. I just wanted to point out your attention that internal electron line is not a real electron because for this virtual particle it is not necessary that p=-m^2, that's all.