Abstract
<jats:p>We present a comprehensive theoretical and computational formulation of the Dead Universe Theory (DUT), a thermodynamic theory of gravitation in which the observed late-time cosmic acceleration, the suppression of large-scale structure growth, and the background expansion emerge from irreversible entropic gravitational dynamics rather than from a positive cosmological constant. Starting from the DUT action, we derive the corresponding autonomous cosmological system and its perturbative sector, demonstrating that the cosmological growth index is a theoretical prediction rather than an observationally calibrated quantity. The asymptotic perturbative dynamics leads uniquely to the characteristic equation γ² + γ − 1 = 0, yielding the fixed solution γ = (√5 − 1)/2 ≈ 0.6180339887 without phenomenological fitting or adjustable parameters.The theoretical framework is implemented through three independent scientific software platforms developed by ExtractoDAO Labs: the TON618 RK4 Engine, the DUT Calibration Engine, and the DUT CMB Scientific Engine. Together, these independent implementations provide computational verification of the theoretical predictions and enable a unified comparison with measurements of the local Hubble constant, the growth-rate observable fσ₈, Pantheon+ Type Ia supernovae, baryon acoustic oscillations, and Planck 2018 CMB distance priors.The DUT framework predicts H₀(local) = 73.88 km s⁻¹ Mpc⁻¹, H₀(CMB) = 67.39 km s⁻¹ Mpc⁻¹, w_eff(z = 0) = −0.9918, and fσ₈(z = 0) = 0.4224. Relative to the reference ΛCDM cosmology, the present implementation yields improvements of Δχ² = −41.09 in the growth sector, Δχ² = −28.76 for the local Hubble constraint, and Δχ² = −211.60 for the combined Pantheon+, BAO, and Planck 2018 CMB distance-prior analysis, corresponding to an overall improvement of Δχ² = −281.45 under the observational datasets analyzed in this work.The DUT framework predicts a unique, fixed value of the cosmological growth index, γA = (√5 − 1)/2 ≈ 0.6180339887, where γA denotes the DUT growth index. This prediction is fully falsifiable: a statistically significant and reproducible measurement inconsistent with γA = 0.6180339887 would refute the perturbative DUT framework without introducing additional parameters or phenomenological recalibration. Unlike cosmological frameworks whose growth predictions are obtained through parameter estimation within a global fit, the DUT prediction constitutes an a priori theoretical result derived directly from first principles. The DUT growth index therefore establishes a quantitative observational benchmark against which competing cosmological theories can be objectively tested.</jats:p>