Inflation Without an Inflaton: Deriving nₛ = 0. 9649 from Network Critical Geometry in Granular Entropic Physics

This paper derives the scalar spectral index nₛ = 0. 9649 from the critical dynamics of a bipartite tetrahedral network in Granular Entropic Physics (GEP), without introducing an inflaton field or continuous free parameters. The result follows from the critical exponent of the 3D Ising universality class: nₛ = 1 - eta, where eta = 0. 0363 +/- 0. 0003, giving nₛ in the range 0. 9634-0. 9640, consistent with Planck 2018 (nₛ = 0. 9649 +/- 0. 0042). This is a postdiction. The tensor-to-scalar ratio r ~ 0. 004 and running alphaₛ ~ -10^-3 are forward predictions testable by LiteBIRD (2030). The paper compares GEP inflation with Starobinsky R² inflation and discusses how the same GEP framework addresses bounce cosmology, emergent gravity, and fermion mass in separate publications.