The Feynman Propagator is given by
[tex] <0| T \phi(y)\phi(x) |0> , [/tex]
where T is the time-ordering operator. I understand that this turns out to be the solution to the inhomogeneous klein-gordon equation, etc., but is there any intuitive description of the propagator? Can this be interpreted, for example, as the propability amplitude for a particle to travel from point x to point y? If so, why? The only thing I have to work with is that [itex] \phi(x) [/itex] is to be interpreted as an operator which creates a particle at point x. But I don't see any notion of time evolution in this definition of the propagator, or anything which is to be interpreted as a 'propagating' particle.