Spurious Effects in perturbative Calculations

TL;DR

This paper investigates the origin of spurious effects in perturbative calculations of Green functions caused by ordering issues, and demonstrates that these effects do not affect physically measurable quantities such as the stress-energy tensor.

Contribution

It identifies and explains the source of spurious effects in perturbative Green function calculations and shows they do not impact physical observables.

Findings

Spurious effects arise from ordering of inhomogeneous terms in perturbation series.

Physically measurable quantities remain unaffected by these spurious effects.

The study clarifies the distinction between mathematical artifacts and physical results.

Abstract

We show spurious effects in perturbative calculations due to different orderings of inhomogeneous terms while computing corrections to Green functions for two different metrics. These effects are not carried over to physically measurable quantities like the renormalized value of the vacuum expectation value of the stress-energy tensor.