Figure 12

Figure 12: Density perturbation enhancement factors (left) and transfer functions (right) from simulations, effective theory, and general relativity. All of the 𝒬 factors monotonically increase with k∕kc, and we see that the Δ amplitude enhancement due to 𝒪 (ρ∕λ ) effects 𝒬ref is generally larger than the enhancement due to KK effects 𝒬 ℰ. For asymptotically small scales k ≫ k c, the enhancement seems to level off. The transfer functions in the right panel are evaluated at a given subcritical epoch in the radiation dominated era. The T functions show how, for a fixed primordial spectrum of curvature perturbations 𝒫inζf, the effective theory predicts excess power in the Δ spectrum 𝒫 Δ ∝ T 2𝒫iζnf on supercritical/subhorizon scales compared to the GR result. The excess small-scale power is even greater when KK modes are taken into account, as shown by T (k;η) 5D. Figure taken from [69].