- #1
robousy
- 334
- 1
Hey folks,
I'm reading Zee 'Introduction to QFT' and have a quick question on some terminology.
On page 10 he describes how:
[tex] \langle q_f|e^{-iHT}|q_i \rangle[/tex] "is the amplitude for a particle to go from some initial state to some final state". He then derives the path integral:
[tex]\langle q_f|e^{-iHT}|q_i \rangle=Z(J)[/tex]
Where
[tex]Z(J)=\mathfont{C}e^{(i/2)\int\int d^4x d^4yJ(x)D(x-y)J(y)}[/tex]
where J(x) is some source and D(x-y) is the propogator. He then says on p23 "Physically D(x-y) describes the amplitude for a disturbance in the field to propagate from y to x".
So, am I correct in saying that Z(J) governs the amplitude of a certain state, eg from one spin state to another, and D(x-y) governs the amplitude of propagation in space from one place to another.
I'm reading Zee 'Introduction to QFT' and have a quick question on some terminology.
On page 10 he describes how:
[tex] \langle q_f|e^{-iHT}|q_i \rangle[/tex] "is the amplitude for a particle to go from some initial state to some final state". He then derives the path integral:
[tex]\langle q_f|e^{-iHT}|q_i \rangle=Z(J)[/tex]
Where
[tex]Z(J)=\mathfont{C}e^{(i/2)\int\int d^4x d^4yJ(x)D(x-y)J(y)}[/tex]
where J(x) is some source and D(x-y) is the propogator. He then says on p23 "Physically D(x-y) describes the amplitude for a disturbance in the field to propagate from y to x".
So, am I correct in saying that Z(J) governs the amplitude of a certain state, eg from one spin state to another, and D(x-y) governs the amplitude of propagation in space from one place to another.