Before all of you cry out "No, stupid, they live in momentum space" I would like to remark that (i) why, then, is there never a momentum-axis attached to them and (ii) the renowned physicist Sivan S. Schweber has included a space-axis in his "An introduction to relativistic quantum field theory" (p. 448). Such a smart guy should have some back thought...
I would think that space and time are proportional to each other in those Feynman diagrams. I visualize an arrangement of narrow strips from photos taken at different moments in time.
Actually, there is quite a good discussion regarding the meaning and interpretation of Feynman diagrams on wikipedia, see the link below. Basically, they show particle paths in space time.
https://en.m.wikipedia.org/wiki/Feynman_diagram
@ Sascha: that is certainly not the case. You seem to think about light travelling always with constant speed (in vacuum) or something like this. What is the speed of a gluon? A quark?
@ Homeier: The discussion is very decent indeed. However, "particle path in space time"? How could this be? Think alone about the fact that the time-ordering of the vertices plays no role in a Feynman diagram (or rather: they are equivalence classes of all diagrams which dffer only by the time-ordering...)
Mainz, Germany
Dear Passon,
I take it that Feyman diagrams are an expression of quantum field theory, originally an expression of quantum electrodynamics. (The point seems to be emphasized in the Wikipedia article.) But all quantum field theory operates on the basis of a background space-time. In consequence, it would seem that whether or not a space axis is explicitly supplied, one could be supplied. Perhaps some Feyman diagrams are more abstract?
H.G. Callaway
Dear Passon, Feynman Diagrams live in a Minkowskian diagram so that have time and space-axis. The important question to remark is all physical (real) processes involved two (or more) particle must have the microcausality property, they must be space-like event since they must no interfer.
they say that Feynman (himself) asked (a few days before he died): what is this all about?
In his Hawking is wrong when he says that the digestive canal would divide (part) a dog in two separated parts, so the dog could not exist, while every being consists of particles which are held toghether (say separately-held) by forces (one would argue: macrocosm versus microcosm, strong force, nuclear force, weak force, but still particles don`t border- there is a wide space between them).
A two dimensional diagram has two axes. There is one for time, and the other?
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