Dissipation of small-scale primordial perturbations after neutrino decoupling cools relic neutrinos and reduces their abundance, enabling PTOLEMY to constrain the primordial curvature power spectrum to O(0.1) on scales k ≲ 3×10^5 Mpc^{-1}.
Knot reconstruction of the scalar primordial power spectrum with Planck, ACT, and SPT CMB data
5 Pith papers cite this work, alongside 5 external citations. Polarity classification is still indexing.
5
Pith papers citing it
5
external citations · Pith
abstract
We investigate a non-parametric Bayesian method for reconstructing the primordial power spectrum (PPS) of scalar perturbations using temperature and polarisation data from the {\em Planck}, ACT, and SPT CMB experiments. This reconstruction method is based on linear splines for the PPS between nodes in $k$-space whose amplitudes and positions are allowed to vary. All three data sets consistently show no significant deviations from a power-law form in the range $0.005 \lesssim k\,\mathrm{Mpc} \lesssim 0.16$ independent of the number of knots adopted to perform the reconstruction. The addition of high-resolution CMB measurements from ACT and SPT slightly improves the range of scales of the scalar PPS which are well constrained around a power law up to $k \simeq 0.25\,\mathrm{Mpc}^{-1}$ and $k \simeq 0.2\,\mathrm{Mpc}^{-1}$, respectively. At large scales, a potential oscillatory feature in the primordial power spectrum appears when we consider six or more nodes. We test the robustness of the methodology and our results by varying the detailed number of knots from $N=2$ to $N=10$. We have used the reconstructed scalar PPS to derive several quantities related to inflationary dynamics, such as the effective scalar spectral index, which describes the dependence of the PPS on the scales and parameters associated with the effective field theory of inflation, to provide information on possible departures from the standard single-field canonical case. Finally, we investigate whether the excess of smoothing in the region of the acoustic peaks of the CMB anisotropy temperature power spectrum in the \textit{Planck} PR3 data is degenerate with our reconstructions of the PPS, but find no significant correlation between them.
citation-role summary
background 2
citation-polarity summary
years
2026 5roles
background 2representative citing papers
BOSS + eBOSS galaxy clustering favors a featureless, quasi-scale-invariant primordial spectrum, with a reconstructed spectral index n_s = 0.976 ± 0.021.
Joint power spectrum and bispectrum analysis from future HI intensity mapping surveys improves constraints on primordial feature amplitudes by 30-40% and achieves percent-level precision on oscillation frequencies when combined with CMB measurements.
Systematic re-analysis of Planck PR3 and PR4 CMB datasets finds local fit improvements of up to Δχ² ≈ -15 for certain oscillatory templates but no global significance above 2.6σ after look-elsewhere correction and Bayesian penalties.
Updated SKAO-AA4 forecasts show multi-tracer HI+galaxy analyses can reach σ(f_local_NL)≲1 and improve αs bounds by tens of percent when combined with future CMB, while foregrounds and GR light-cone effects remain the main systematics.
citing papers explorer
-
Probing the small-scale primordial power spectrum via relic neutrinos and acoustic reheating
Dissipation of small-scale primordial perturbations after neutrino decoupling cools relic neutrinos and reduces their abundance, enabling PTOLEMY to constrain the primordial curvature power spectrum to O(0.1) on scales k ≲ 3×10^5 Mpc^{-1}.
-
Primordial power spectrum reconstructions from BOSS + eBOSS
BOSS + eBOSS galaxy clustering favors a featureless, quasi-scale-invariant primordial spectrum, with a reconstructed spectral index n_s = 0.976 ± 0.021.
-
Searching for primordial features with radio surveys: synergy between the power spectrum and bispectrum
Joint power spectrum and bispectrum analysis from future HI intensity mapping surveys improves constraints on primordial feature amplitudes by 30-40% and achieves percent-level precision on oscillation frequencies when combined with CMB measurements.
-
Signals from the early Universe: a comprehensive search for primordial features in Planck CMB datasets
Systematic re-analysis of Planck PR3 and PR4 CMB datasets finds local fit improvements of up to Δχ² ≈ -15 for certain oscillatory templates but no global significance above 2.6σ after look-elsewhere correction and Bayesian penalties.
-
Beyond {\Lambda}CDM with the SKA Observatory -- II: Unveiling the Secrets of the Early Universe
Updated SKAO-AA4 forecasts show multi-tracer HI+galaxy analyses can reach σ(f_local_NL)≲1 and improve αs bounds by tens of percent when combined with future CMB, while foregrounds and GR light-cone effects remain the main systematics.