Cosmology from Two Axioms 2: Cosmological Constant from Information Conservation—Vacuum Computational Complexity Gradient as a Quantitative Predictor for Λ and Observational Tests

Within the framework established by the two fundamental principles of “Information Conservation” and “Computability of Physical Laws”, this paper proposesa novel interpretation of the origin and evolution of the cosmological constant (Λ).We relate Λ to the computational complexity gradient (∇Cvac) of the quantumvacuum state, arguing that under the premise of total information conservation,a non-zero complexity gradient can generate an effective positive energy densityequivalent to a cosmological constant. Based on this mechanism, the model naturally derives a power-law form for the evolution of Λ with the cosmic scale factor:Λ(a) ∝ a−α. Through a joint analysis of contemporary mainstream observationaldata—including the Pantheon+ supernovae, DESI baryon acoustic oscillations, andthe Planck lensing potential power spectrum—we determine the best-fit value forthe evolution index to be α = 1.52±0.03. This model not only provides a superiordescription of the current data but, more crucially, its core prediction (α ≈ 1.52)can be directly tested at a confidence level above 5σ using next-generation astronomical observation facilities (such as SKA and the Roman Space Telescope),thereby possessing clear falsifiability.