Unified Constraint Theory

I present the Unified Constraint Theory (UCT), a minimal effective-field-theory framework in which high-curvature gravitational dynamics are systematically regulated by afinite cutoff scale Ωmax. The theory naturally extends Starobinsky R+R2 inflation, introducing a smooth suppression of higher-curvature contributions above Ω2max while preserving the canonical scalar–tensor structure. UCT propagates only the massless graviton and a single scalar degree of freedom, with no Ostrogradsky instabilities, and maintains luminal tensor propagation speed, consistent with current gravitational-wave constraints. In the limit Ωmax → ∞, UCT reduces exactly to Starobinsky inflation, reproducing the plateau potential and its standard slow-roll predictions for the scalar spectral index ns and tensor-to-scalar ratio r. For finite Ωmax, deviations are parametrically suppressed by R/Ω2max, and current CMB observations imply Ωmax lies safely above the inflationary curvature scale. The regulator is shown to be technically natural and physically predictive: renormalized observables are independent of the regularization scheme, and the EFT expansion remains self-consistent. The framework therefore bridges ultraviolet regularization and observable inflationary physics, providing a falsifiable, controlled generalization of curvature-driven inflation. UCT opens a pathway to explore how fundamental high curvature constraints shape the early universe while remaining consistent with low curvature cosmological observations.