QFT Propagator Poles

physicsquantum field theorycomplex analysisGreen's functionpropagatorscausalityMatsubaracetztikz

Complex plane visualization of propagator poles and branch cuts in quantum field theory. The diagram shows the analytic structure of Green's functions, including the relationship between retarded/advanced propagators and the placement of poles relative to the real axis. This structure helps understand causality and the connection to Matsubara frequencies.