Universal Fluid Cosmology: A Superfluid Origin for Dark Matter, Geometric Bulk Viscous Pressure for Dark Energy, and a Zero-Parameter Derivation of the Spectral Index

This paper summarizes the Universal Fluid Cosmology (UFC), a framework in which the universe is a superfluid governed by the full nonlinear compressible Navier-Stokes equations. What ΛCDM attributes to dark energy is reinterpreted as the geometric bulk viscous pressure of a three-dimensional superfluid, with bulk viscosity ζ = ρₘ c²/ (αB H) where the geometric coupling αB = d³/ (d²−2) = 27/7 for d=3, yielding w = −d/αB = −7/9 ≈ −0. 778 with zero free parameters. Dark matter is the condensed phase of the same fluid, producing flat galaxy rotation curves via isothermal hydrostatic equilibrium. The Friedmann equation is shown to be structurally identical to the Chapman-Jouguet (CJ) detonation equation; the cellular instability of this detonation yields a spectral index nₛ = 0. 9652, matching Planck to 0. 1σ with no tuning. The matter density Ωₘ = 0. 310 is derived from the Bogoliubov excitation spectrum of the broken superfluid. Against DESI w₀-wₐ data with full covariance, UFC achieves χ² = 16. 5 versus ΛCDM's 16. 8. Rotation curves (including the inner rotation curve problem, resolved by solitonic cores from the Gross-Pitaevskii-Poisson ground state) win 121/171 SPARC galaxies over NFW on raw χ². The mutual friction coefficient Bₘf that fits CMB acoustic peaks simultaneously predicts primordial deuterium through Beer-Lambert acoustic dissipation with gravitational bandpass: D/H = 2. 52 × 10⁻⁵ (< 0. 1σ from observation) with zero free parameters, linking CMB and BBN through a single derived parameter. All results flow from one input: d = 3 spatial dimensions.