Srednicki — Quantum Field Theory · Problem 8.5

Canonical Quantization of Scalar Fields — Mark Srednicki

Physics — QFT · path-integral-free-field-theory

Problem

The retarded and advanced Green's functions for the Klein-Gordon wave operator satisfy

\Delta_{\mathrm{ret}}(x-y) = 0

for

x^0 \geq y^0

and

\Delta_{\mathrm{adv}}(x-y) = 0

for

x^0 \leq y^0

. Find the pole prescriptions on the right-hand side of eq. (8.11) that yield these Green's functions.