Normalized Ramanujan tau τ̃(p) = τ(p)·p^(-11/2) for consecutive primes, where τ(n) is the q-coefficient of Δ(q) = η(q)^24 — the unique weight-12 cusp form on SL(2,ℤ). By Deligne (1974, formerly Ramanujan-Petersson), |τ̃(p)| ≤ 2 for all p; by Barnet-Lamb–Geraghty–Harris–Taylor (2011), {τ̃(p)} equidistributes to the Sato-Tate semicircle (2/π)√(1-x²/4) on [-2,2] — a non-Gaussian, non-uniform universal distribution distinct from GUE/Wigner spacing. Calibration anchor for metrics responding to semicircle-distributed sequences with deep automorphic structure.
Standard analysis sees: rich, high-entropy values; aperiodic / broadband; high-complexity (noise-like); high-dimensional / space-filling. The atlas finds no named structure, but the source is distinctively extreme on Boltzmann:coupling_temporal_variance (+2.3z) — beyond what the standard bank predicts for it.
Boltzmann:coupling_temporal_variance | +2.3z | bank-miss 1.0σ |








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| Nearest neighbor | Distance | |
|---|---|---|
| ChaCha20 | 2.34 | cross-domain |
| Wichmann-Hill | 2.48 | cross-domain |
| Wigner Semicircle | 2.52 | cross-domain |
Boltzmann › Boltzmann:coupling_strength | rank 295/298 | 0.0051 |
Cantor Set › Cantor Set:bit_plane_autocorrelation | rank 296/298 | 0.0024 |
Catch24 › Catch24:SB_MotifThree_quantile_hh | rank 1/298 | 2.1972 |
Catch24 › Catch24:SB_TransitionMatrix_3ac_sumdiagcov | rank 298/298 | 0.0000 |
D4 Triality › D4 Triality:gram_consistency | rank 1/298 | 2.5205 |
D4 Triality › D4 Triality:spectral_transition | rank 3/298 | 0.2480 |
Heisenberg (Nil) (centered) › Heisenberg (Nil) (centered):area_length_ratio | rank 295/298 | 0.0000 |
Möbius-S³ › Möbius-S³:phase_profile_deviation | rank 296/298 | 0.1103 |
Predictability › Predictability:sample_entropy | rank 3/298 | 2.2361 |
Spherical S² › Spherical S²:spectral_gini | rank 296/298 | 0.3216 |
S² × ℝ (Thurston) › S² × ℝ (Thurston):bingham_concentration | rank 297/298 | 0.4100 |