RG-Constrained Cosmology and the Origin of Horizon Entropy

We show that late-time cosmological dynamics admits a unique information-theoretic representation once renormalization-group (RG) constraints are combined with an operational definition of irreversible information. Infrared RG scaling of the vacuum sector, together with Bianchi consistency, reduces the cosmological evolution to a one-dimensional trajectory characterized by the invariantH Ω_Λ^1/θ = const. Independently, within nonequilibrium thermodynamics, physically meaningful information is carried only by stabilized irreversible transitions, quantified by the Valid Irreversible Resolution Rate (VIRR), which is not reducible to entropy production. We demonstrate that these two structures are mutually consistent only if horizon entropy is a derived quantity determined by the vacuum fraction. This leads to a uniquely fixed entropy production law, dSH/dt ∝ Ω_Λ^1/θ (1 − Ω_Λ), with a logistic form exhibiting a single maximum at Ω_Λ = 1/ (1 + θ). The framework predicts a direct observational signature: the location of maximal entropy production provides an estimator of the RG critical exponent and establishes a falsifiable link between RG dynamics and cosmological data. In this picture, cosmic expansion admits a dual description: as evolution along an RG-invariant trajectory and as a constrained growth of physically stabilized information. The asymptotic de Sitter state corresponds to saturation of accessible configurations. These results establish a quantitative bridge between RG cosmology and nonequilibrium information thermodynamics, identify horizon entropy as a derived rather than fundamental quantity, and provide a potential dynamical perspective on current cosmological tensions.