Causal amplitudes in the Schwinger model at finite temperature

TL;DR

This paper demonstrates that in the Schwinger model at finite temperature, all temperature-dependent retarded and advanced amplitudes vanish, due to CPT invariance, with a physical interpretation involving on-shell thermal particles.

Contribution

It reveals that temperature-dependent amplitudes vanish in the Schwinger model at finite temperature, highlighting the role of CPT invariance and forward scattering interpretations.

Findings

Temperature-dependent retarded and advanced amplitudes vanish

CPT invariance explains the vanishing behavior

Physical interpretation involves forward scattering of thermal particles

Abstract

We show, in the imaginary time formalism, that the temperature dependent parts of all the retarded (advanced) amplitudes vanish in the Schwinger model. We trace this behavior to the CPT invariance of the theory and give a physical interpretation of this result in terms of forward scattering amplitudes of on-shell thermal particles.