Predictions→ NANOGrav GW Background
NANOGrav GW Background
The matter bounce predicts an induced gravitational wave spectral index γ = 3.0 from primordial perturbation growth during contraction. The R42 Wave 13 emcee run on the real NANOGrav 15-yr HD-correlated KDE free-spectrum (Zenodo 8060824, 30 Fourier bins, 32 walkers × 10K production) recovers γ = 2.567 ± 0.382 — bounce 3.0 sits at -1.13σ, SMBHB γ = 4.33 is excluded at -4.6σ.
NANOGrav 15yr real-KDE free-spectrum: γ = 2.567 ± 0.382 (median 2.591, 68% CI [2.304, 2.882]); log10_A = -14.025 ± 0.380. Bounce γ = 3.0 consistent at -1.13σ. SMBHB γ = 4.33 excluded at -4.6σ. Supersedes the prior synthetic-power-law summary statistic γ = 3.20 ± 0.42; the real-vs-synthetic shift is -1.48σ. ESS = 5,507; autocorr τ ≈ 58; acceptance = 0.63.
- Wave 13 real-KDE: γ = 2.567 ± 0.382 (matter bounce 3.0 at -1.13σ)
- SMBHB γ = 4.33 excluded at -4.6σ (sharper than the synth-PL exclusion of ~2.7σ)
- Real-vs-synthetic shift: -1.48σ — substantive, not cosmetic
- Wave 13 emcee: 32 walkers × 10K production + 2.5K burn-in, ESS = 5,507, τ ≈ 58
- PBH-induced GW spectrum consistent with observed amplitude