- #1
vishal.ng
- 2
- 1
I'm studying QFT in the path integral formalism, and got stuck in deriving the Schwinger Dyson equation for a real free scalar field,
L=½(∂φ)^2 - m^2 φ^2
in the equation,
S[φ]=∫ d4x L[φ]
∫ Dφ e^{i S[φ]} φ(x1) φ(x2) = ∫ Dφ e^{i S[φ']} φ'(x1) φ'(x2)
Particularly, it is in the Taylor series expansion of the functional exponential
e^{i S[φ']}=e^{i S[φ+iα]} . Can anybody please tell me about the expansion? I have searched and haven't found anything quite helpful on the net. Thank you.
L=½(∂φ)^2 - m^2 φ^2
in the equation,
S[φ]=∫ d4x L[φ]
∫ Dφ e^{i S[φ]} φ(x1) φ(x2) = ∫ Dφ e^{i S[φ']} φ'(x1) φ'(x2)
Particularly, it is in the Taylor series expansion of the functional exponential
e^{i S[φ']}=e^{i S[φ+iα]} . Can anybody please tell me about the expansion? I have searched and haven't found anything quite helpful on the net. Thank you.