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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representative citing papers
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citing papers explorer
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Cosmological analysis of the DESI DR1 Lyman alpha 1D power spectrum
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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 beams and asymmetric scans.
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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.
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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
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.
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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 mass sum to < 0.071 eV.
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Dark Energy Survey Year 3 Results: Cosmological Constraints from Galaxy Clustering and Weak Lensing
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SWIM: Stochastic Warm Inflation Module to generate and analyse Warm Inflationary power spectrum
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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 on Linear Scales in a Dynamical Dark Energy Background
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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.
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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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Resolving the Hubble Tension in the Early Dark Energy Framework with JWST and DESI Data
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Signals from the early Universe: a comprehensive search for primordial features in Planck CMB datasets
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Constraints of dynamical dark energy models from different observational datasets
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New Insights into Dark Energy from DESI DR2 with CMB and SNIa
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Extended Dark Energy analysis using DESI DR2 BAO measurements
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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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cloelib: A Flexible Python Library for Computing Cosmological Observables in the Euclid Era
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ACT DR6+Planck impact on inflation with non-zero vacuum expectation value and the post-inflationary behavior
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CMB power spectra and cosmological parameters from Planck PR4 with CamSpec
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