Traversable Wormholes at Intermediate Scales from Non-Minimal Curvature–Gauge Couplings in Effective Field Theory (FST Framework)

We present the Frozen Scalar-Throat (FST) framework, a self-consistent construction within the effective field theory (EFT) of gravity in which non-minimal curvature–gauge couplings of order M_P⁻² between spacetime curvature and Standard Model gauge fields allow for traversable wormhole solutions at intermediate scales. The key ingredient is a dimensionless coupling constant |α| ~ 10⁻⁶, which lies within the EFT convergence domain and is consistent with all existing experimental bounds. The energy–momentum tensor derived from the non-minimal coupling Rℱ is computed exactly via variational principles, yielding a geometrically sourced effective energy density that dynamically violates the Weak Energy Condition (WEC) without introducing exotic matter by hand. We prove that the Dirac magnetic monopole ansatz remains an exact solution of the modified gauge field equations in a spherically symmetric curved background (Theorem 3), and we construct self-consistent numerical solutions for the wormhole metric profile. A complete linear stability analysis is performed using the full master equation for multipole perturbations with ℓ ≥ 0. The resulting quasi-normal mode spectrum shows that the wormhole is stable against radial and non-radial perturbations for -8 × 10⁻⁶ < α < -2 × 10⁻⁷. We derive three independent, falsifiable experimental predictions: (i) a scalar polarization mode in gravitational waves with h_s/h_t ~ 10⁻⁸; (ii) scalar–tensor correlations in the CMB with C_ℓST ~ O(10⁻⁵–10⁻¹) μK^2 depending on H_inf; and (iii) modifications to the small-scale CMB power spectrum at ℓ > 2000. The theory is explicitly falsifiable: within projected detector sensitivities, a non-detection across all three channels by next-generation experiments (LIGO A+, Cosmic Explorer, CMB-S4, Einstein Telescope) would severely constrain the model. This deposit includes the complete manuscript (PDF) and the verified Python numerical solver (Appendix B) with unit tests.