Standard inflationary models predict primordial gravitational waves at amplitude r in the range characteristic of high-scale inflation (V¹⁄⁴ ~ 10¹⁶ GeV). BICEP/Keck + Planck have tightened the upper limit to r < 0.036 (95% CL), with future targets at r ~ 10⁻³ (BICEP/Keck 2021; Ye & Piao 2022). Continued non-detection challenges generic single-field inflation, forcing fine-tuning of inflaton potentials.
The standard model with inflation requires primordial gravitational waves at amplitude observable by upcoming CMB-B-mode experiments. Recovering tighter and tighter null results within ΛCDM demands either highly fine-tuned inflationary potentials or abandoning simple single-field inflation, neither of which is parsimonious within the standard framework.
SCT replaces the hot-dense-center with a superluminal collision and the thermalized debris field. From this single change, no inflationary epoch ever occurred in our cosmological history. The cascade infrastructure (P22, P25, P26, P36, P37, P38) replaces inflation: cascade-stream thermalization solves the horizon problem (recid 14), the flatness problem (recid 10), and the structure-seeding problem without requiring inflation. There is no inflaton field in SCT, so no primordial gravitational waves are generated by inflation.
SCT predicts r < 10⁻⁵ permanently, far below the BICEP/Keck upper bound and the LiteBIRD + CMB-S4 design sensitivity targets. Cascade-stage gravitational-wave production (P22, P36) operates at QCD-scale energies far below the inflationary scale; the resulting cascade-epoch GW background is negligible at CMB scales. Continued non-detection of B-modes by CMB-S4 + LiteBIRD will directly support SCT and disfavor inflation as a cosmologically necessary mechanism.
This is the cleanest near-term M1 falsifier: a single confirmed primordial B-mode detection at r > 0.005 would refute SCT's no-inflation cascade cosmology. Conversely, the increasingly tight null results across decades of inflation-targeting experiments are exactly what SCT predicts. The same M1 framework that resolves the horizon problem (recid 14), flatness (recid 10), hierarchy (recid 6), monopole-absence (recid 21), and broader inflation-replacing infrastructure accounts for the r < 0.01 tensor limit as a cascade prediction.
Detection of primordial B-modes at r > 0.005 (LiteBIRD, CMB-S4) at greater than 5σ would refute the no-inflation cascade cosmology and re-introduce inflation as physically required. This is the cleanest single falsifier of M1.