CMB power spectrum parameter degeneracies in the era of precision cosmology
read the original abstract
Cosmological parameter constraints from the CMB power spectra alone suffer several well-known degeneracies. These degeneracies can be broken by numerical artefacts and also a variety of physical effects that become quantitatively important with high-accuracy data e.g. from the Planck satellite. We study degeneracies in models with flat and non-flat spatial sections, non-trivial dark energy and massive neutrinos, and investigate the importance of various physical degeneracy-breaking effects. We test the CAMB power spectrum code for numerical accuracy, and demonstrate that the numerical calculations are accurate enough for degeneracies to be broken mainly by true physical effects (the integrated Sachs-Wolfe effect, CMB lensing and geometrical and other effects through recombination) rather than numerical artefacts. We quantify the impact of CMB lensing on the power spectra, which inevitably provides degeneracy-breaking information even without using information in the non-Gaussianity. Finally we check the numerical accuracy of sample-based parameter constraints using CAMB and CosmoMC. In an appendix we document recent changes to CAMB's numerical treatment of massive neutrino perturbations, which are tested along with other recent improvements by our degeneracy exploration results.
This paper has not been read by Pith yet.
Forward citations
Cited by 18 Pith papers
-
Cosmological analysis of the DESI DR1 Lyman alpha 1D power spectrum
DESI DR1 Lyman-alpha data yields Δ²★=0.379±0.032 and n★=-2.309±0.019 at k★=0.009 km⁻¹s and z=3, sharpening N_eff, α_s, and β_s constraints by factors of 1.18-1.90 when combined with other probes.
-
Deep Learning for CMB Foreground Removal and Beam Deconvolution: A U-Net GAN Approach
A U-Net GAN reconstructs CMB T and E maps from Planck-like simulations with foregrounds and systematics, achieving under 1% error outside the Galactic region and demonstrating first-time correction for non-circular be...
-
DESI 2024 VI: Cosmological Constraints from the Measurements of Baryon Acoustic Oscillations
First-year DESI BAO data are consistent with flat LambdaCDM and, when combined with CMB, show a 2.5-3.9 sigma preference for evolving dark energy (w0 > -1, wa < 0) that strengthens with certain supernova datasets.
-
Cobaya: Code for Bayesian Analysis of hierarchical physical models
Cobaya is a modular Bayesian analysis code that exploits model interdependencies via automatic caching and a novel parameter-blocking algorithm to minimize sampling cost.
-
Modeling nonlinear scales for dynamical dark energy cosmologies with COLA
COLA-based hybrid emulator reproduces nonlinear power spectrum boosts in w0wa models to <2% error vs EuclidEmulator2 and produces <0.3σ shifts in LSST-like cosmic shear parameter constraints.
-
DESI 2024 VII: Cosmological Constraints from the Full-Shape Modeling of Clustering Measurements
DESI DR1 full-shape clustering yields Ω_m = 0.2962 ± 0.0095 and σ_8 = 0.842 ± 0.034 in flat ΛCDM, tightening to H_0 = 68.40 ± 0.27 km/s/Mpc with CMB and DESY3, while favoring w_0 > -1, w_a < 0 and limiting neutrino ma...
-
Dark Energy Survey Year 3 Results: Cosmological Constraints from Galaxy Clustering and Weak Lensing
DES Y3 3x2pt analysis constrains S8=0.776±0.017 and Ωm=0.339±0.032 in flat ΛCDM, consistent with Planck CMB results at p=0.13-0.48.
-
Signatures of Modified Gravity Below $\mathcal{O}(10)$ Mpc in a Dynamical Dark Energy Background
Modified gravity below O(10) Mpc in a CPL dynamical dark energy background is required to suppress structure growth at low redshifts while satisfying CMB constraints from ISW and lensing.
-
SWIM: Stochastic Warm Inflation Module to generate and analyse Warm Inflationary power spectrum
SWIM is a publicly available numerical platform that generates full Warm Inflation scalar power spectra and enables MCMC parameter estimation with CMB data for arbitrary potentials and dissipation forms.
-
A generic $\omega_b$ tension in early-time solutions to the Hubble tension
Early-time Hubble tension solutions generically raise the preferred baryon density ω_b, conflicting with BBN deuterium constraints and producing poorer fits to CMB, BAO, supernova, and BBN data than ΛCDM.
-
Thawing Quintessence: Priors, evidence, and likely trajectories
Bayesian evidence from DESI DR2 BAO, Planck+ACT CMB, and multiple supernova samples favors thawing quintessence over a cosmological constant.
-
Constraints of dynamical dark energy models from different observational datasets
Bayesian constraints on seven w(a) parameterizations with CMB+BAO+SNIa datasets favor the logarithmic model over LambdaCDM in several combinations and show modest sigma8 relief.
-
New Insights into Dark Energy from DESI DR2 with CMB and SNIa
Systematic dataset swaps show DESY5 low-redshift SNIa, Planck CMB plus lensing, and DESI-DR2 BAO as the dominant sources of w0waCDM tension with ΛCDM, while other combinations remain consistent.
-
Extended Dark Energy analysis using DESI DR2 BAO measurements
Extended analysis of DESI DR2 data confirms robust evidence for dynamical dark energy with phantom crossing preference, stable under parametric and non-parametric modeling.
-
cloelike: A Python Library for Cosmological Likelihood Inference in the Euclid Era
cloelike is a new open Python package implementing composable Gaussian likelihoods for WL, GCph, GGL, full-shape spectra, and BAO in joint probe combinations for Euclid analyses.
-
cloelib: A Flexible Python Library for Computing Cosmological Observables in the Euclid Era
cloelib is a modular JAX-based Python library for cosmological observables intended as reference infrastructure for Euclid's first data release.
-
ACT DR6+Planck impact on inflation with non-zero vacuum expectation value and the post-inflationary behavior
Updated constraints on non-zero VEV parameter M from ACT+Planck data, plus lattice simulations showing oscillon formation and reheating implications.
-
CMB power spectra and cosmological parameters from Planck PR4 with CamSpec
Planck PR4 NPIPE maps processed with CamSpec produce LCDM parameters consistent with 2018 results but with ~10% tighter constraints and shifts toward LCDM values for extensions like Omega_K and A_Lens.
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.