Here’s the main takeaway for CMB angular power spectra:
TT (Temperature): Standard on large scales ( ℓ≲30 ℓ≲30), but small-scale power ( ℓ≳1000 ℓ≳1000) is exponentially damped due to the diffusive evolution of perturbations.
EE (E-mode polarization): Peaks are broadened and suppressed.
TE (Temperature-E polarization cross-correlation): Anti-correlation around ℓ∼100 ℓ∼100 is reduced.
BB (B-mode polarization): Essentially no primordial signal, only lensing contributes.
Key prediction: This model is falsifiable because it predicts suppressed high- ℓ ℓ power and negligible primordial B-modes, in contrast to standard ΛCDM + inflation.