Persistence of trajectory dependence across broader interacting models

Determine whether the dependence of the inferred dark-sector interaction on the assumed dark-energy trajectory persists across a broader class of interacting dark-energy models with interaction terms other than Q=βHρ_de or with momentum-transfer prescriptions other than energy-momentum transfer parallel to the cold-dark-matter four-velocity.

Background

The analysis adopts the specific interaction Q=βHρ_de, assumes that the energy-momentum transfer is parallel to the cold-dark-matter four-velocity, and examines only several phenomenological parameterizations of the intrinsic dark-energy evolution. Within this restricted framework, the statistical preference for an interaction varies strongly with the chosen dark-energy trajectory: it is negligible for the general CPL and mirage models but substantial for the thawing and GEDE models, with opposite preferred coupling signs.

The authors explicitly identify the need to test whether this trajectory dependence is a generic property of interacting dark-energy scenarios or instead a consequence of the chosen interaction and momentum-transfer prescriptions. Resolving this question would establish how robust the reported degeneracy between intrinsic dark-energy dynamics and dark-sector interactions is beyond the specific phenomenological framework studied.