All-multiplicity organization beyond the all-plus Abelian sector

Determine whether a comparable all-multiplicity organization exists beyond the all-plus Abelian sector, including settings with mixed photon helicities or non-Abelian gauge-boson self-interactions.

Background

The paper derives a compact all-multiplicity recursion for tree-level late-time wavefunction coefficients in the all-plus sector of scalar QED in four-dimensional de Sitter space. The construction relies on the vanishing of the common-reference auxiliary contraction for higher-point coefficients and on Abelian Ward identities that reduce the result to lower-point coefficients with shifted charged-scalar momenta.

The authors identify extending this organization as unresolved beyond the all-plus Abelian setting. Mixed photon helicities may invalidate the vanishing common-reference contraction, while non-Abelian theories add gauge-boson self-interactions. Existing higher-point Yang–Mills results and four-point all-plus expressions are cited as potential starting points for addressing this problem.