On Dark-Sector Scalar Field Theories Driven by Cosmological c-Fields

The interplay of Hoyle–Narlikar (HN) creation field cosmology and scalar field models for the dark sector, including the Generalized Chaplygin gas (GCG) model, is investigated. Though originating from distinct theoretical frameworks, both the inclusion and the non-inclusion of the creation field degree of freedom (DoF) involve a scalar DoF, which addresses some of the limitations of the standard ΛCDM model. Using a Lagrangian scalar field formulation and the first-order Hamiltonian reconstruction method, the HN c-field dynamics are shown to be encompassed by the GCG equation of state through an equivalent modified scalar field theory. Late-time acceleration and stability of linear perturbations are derived within this unified description. Our results suggest that creation field cosmologies may be embedded in a broader class of scalar field models which encompasses subtle modifications to the Hubble expansion rate and related physical observables.