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.
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CMB power spectrum parameter degeneracies in the era of precision cosmology
Mixed citation behavior. Most common role is method (62%).
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.
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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.
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Modeling nonlinear scales for dynamical dark energy cosmologies with COLA
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DESI 2024 VII: Cosmological Constraints from the Full-Shape Modeling of Clustering Measurements
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Dark Energy Survey Year 3 Results: Cosmological Constraints from Galaxy Clustering and Weak Lensing
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Revisiting the 'Lensing is Low' Problem with UNIONS
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Reconstructing dark energy with fewer assumptions
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Signatures of Modified Gravity Below $\mathcal{O}(10)$ Mpc in a Dynamical Dark Energy Background
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Thawing Quintessence: Priors, evidence, and likely trajectories
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SWIM: Stochastic Warm Inflation Module to generate and analyse Warm Inflationary power spectrum
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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.
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Intertwined Constraints in Extended Cosmologies: Dark Energy, Curvature, Neutrinos, and Inflation
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Resolving the Hubble Tension in the Early Dark Energy Framework with JWST and DESI Data
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CMB power spectra and cosmological parameters from Planck PR4 with CamSpec
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Dark Energy in the DESI Era: A Brief Review of Evidence, Beyond-$\Lambda$CDM Interpretations, and Tensions
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