Information–Driven Late–Time Cosmology: A Precision Test of the InfoCDM and InfoCDM+ Models

This work presents a precision late–time cosmological analysis of two information–driven dark–energy models, InfoCDM and InfoCDM+.Both models arise as phenomenological limits of an underlying informational–gravity framework, where the dark–energy density is encoded in a smooth deformation function models are defined by:InfoCDM: f(z) = 1 + α zInfoCDM+: f(z) = 1 + α z + β z^2 modifying the standard ΛCDM expansion history. Using a unified numerical pipeline, we confront ΛCDM, InfoCDM, and InfoCDM+ with 1048 Pantheon Type Ia supernovae, 25 cosmic–chronometer H(z) measurements, 4 BAO DV/rₑₐₚ ratios, and the Planck CMB shift parameter.The information–based models provide improved χ² values relative to ΛCDM, especially in the SN and CC sectors, while remaining consistent with BAO and CMB constraints.Both InfoCDM and InfoCDM+ predict a mildly phantom present–day equation of state and an acceleration transition near transition redshift z_t ≈ 0.70. This article establishes that smooth, low–order informational deformations of the late–time dark–energy density constitute a compact, stable, and observationally competitive alternative to the cosmological constant.The preferred deformation parameters naturally map onto the small–field expansion of the informational scalar field, linking phenomenological cosmology to the underlying InfoGR framework.