Resolve gauge dependence of quantum-corrected effective field equations

Resolve the remaining gauge dependence of quantum-corrected effective field equations in quantum field theory on cosmological backgrounds, including the dependence of one-particle-irreducible functions and their solutions on the graviton gauge choice.

Background

The paper identifies gauge dependence as the third major difficulty in interpreting loop-corrected effective field equations. Although the Schwinger–Keldysh formalism addresses reality and causality, the authors state that removing gauge dependence requires additional constructions involving quantum gravitational correlations with the source and observer.

The paper develops and applies such a procedure to the one-loop self-mass of a massless, minimally coupled scalar on de Sitter space, but the introductory statement concerns the broader unresolved problem of formulating gauge-independent effective field equations on cosmological backgrounds.

References

Issues such as gauge invariance, vacuum dependence, and non-perturbative resummation remain open and require further investigation.

— Spectral Suppression of Asymptotic States in Supersymmetric QFT on de Sitter Backgrounds  (2609.10814 - Bellucci et al., 9 Sep 2026) in Section 1, paragraph following Eq. (effective residue); Remark immediately following the effective infrared suppression derivation

Resolving the third problem, gauge dependence, requires more work, and is still an open problem.

— Universal Secular External Leg Corrections for Gauge Independent Scalar Self-Mass on de Sitter  (2609.10365 - Glavan et al., 9 Sep 2026) in Section 1, Introduction