Informational Gravity IV: Vacuum Structure and the Cosmological Constant

This preprint (Paper IV in the Informational Gravity series) develops an interpretive framework in which spacetime, gravity, and thermodynamic phenomena are treated as emergent from the informational structure of bound energy. Building on the “finite capacity -> residual fluctuations” motivation from Paper III, it argues that vacuum fluctuations are physically real but that the gravitationally relevant vacuum scale is set by cosmological-horizon (boundary) degrees of freedom rather than the naive QFT bulk mode sum. The quantitative core is an algebraic identity built from Bekenstein - Hawking entropy, Gibbons - Hawking temperature, and the Landauer bound, showing that the resulting horizon energy scale divided by the Hubble volume yields the critical-density scale rho_crit with no free parameters. The identity is explicitly scale-setting: it yields rho_crit, not the observed rho_Lambda ~= 0.69 rho_crit, and it does not by itself derive the dark-energy equation of state. The paper also gives an algebraic comparison (up to O(1) geometric factors) with Sorkin’s causal-set everpresent-Lambda scaling and includes a quantitative no-go result for a previously proposed bulk “link dissolution” mechanism.