One Extension to Explain Them All, One Scale-Invariant Spectrum to Test Them All, and in One Model Bind Them

Abstract

The increasing precision of Cosmic Microwave Background (CMB) observations has unveiled significant tensions between different datasets, notably between Planck and the Atacama Cosmology Telescope (ACT), as well as with the late-Universe measurements of the Hubble constant. In this work, we explore a variety of $\Lambda$CDM extensions to assess their ability to reconcile these discrepancies. The statistical preference for these extensions remains moderate, and imposing $n_s=1$ often worsens model performance. Our findings highlight the limitations of incremental modifications to $\Lambda$CDM and suggest that either more complex new physics or, more likely, improved systematic understanding in the CMB sector may be required to fully address the observed tensions. While CMB experiments are often considered the gold standard of precision cosmology, our results reinforce that these measurements are not immune to systematic uncertainties, which may be underestimated in current analyses.

arXiv comment24 pages, 7 tables, 7 figures. v2: minor corrections

References in corpus (185)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• Planck 2015 results. XIII. Cosmological parameters
• Planck 2013 results. XVI. Cosmological parameters
• Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results
• Efficient Computation of CMB anisotropies in closed FRW models
• Cosmological Imprint of an Energy Component with General Equation of State
• The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: cosmological analysis of the DR12 galaxy sample
• Cosmology and the Fate of Dilatation Symmetry
• Planck 2018 results. X. Constraints on inflation
• Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Final Maps and Results
• The Cosmic Linear Anisotropy Solving System (CLASS) II: Approximation schemes
• A Comprehensive Measurement of the Local Value of the Hubble Constant with 1 km/s/Mpc Uncertainty from the Hubble Space Telescope and the SH0ES Team
• Phantom Energy and Cosmic Doomsday
• The Clustering of the SDSS DR7 Main Galaxy Sample I: A 4 per cent Distance Measure at z=0.15
• Planck 2018 results. I. Overview and the cosmological legacy of Planck
• The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Cosmological Implications from two Decades of Spectroscopic Surveys at the Apache Point observatory
• Bayes in the sky: Bayesian inference and model selection in cosmology
• 4-Year COBE DMR Cosmic Microwave Background Observations: Maps and Basic Results
• Tensions between the Early and the Late Universe
• A 6% measurement of the Hubble parameter at $z\sim 0.45$: direct evidence of the epoch of cosmic re-acceleration
• Planck 2018 results. V. CMB power spectra and likelihoods
• Challenges for $\Lambda$CDM: An update
• Reconstructing the Inflaton Potential --- an Overview
• Relic neutrino decoupling including flavour oscillations
• Cobaya: Code for Bayesian Analysis of hierarchical physical models
• The Atacama Cosmology Telescope: DR4 Maps and Cosmological Parameters
• Planck evidence for a closed Universe and a possible crisis for cosmology
• Measurements of the Hubble Constant: Tensions in Perspective
• CMB power spectrum parameter degeneracies in the era of precision cosmology
• New physics in light of the $H_0$ tension: an alternative view
• The linear power spectrum of observed source number counts
• The Cosmic Linear Anisotropy Solving System (CLASS) I: Overview
• A Measurement of the Damping Tail of the Cosmic Microwave Background Power Spectrum with the South Pole Telescope
• The Expansion of the Universe is Faster than Expected
• The $H_0$ Olympics: A fair ranking of proposed models
• Calibration of the Tip of the Red Giant Branch (TRGB)
• The effects of He I 10830 on helium abundance determinations
• The Atacama Cosmology Telescope: Cosmological Parameters from the 2008 Power Spectra
• Curvature tension: evidence for a closed universe
• Cosmological bounds on neutrino degeneracy improved by flavor oscillations
• TDCOSMO IV: Hierarchical time-delay cosmography -- joint inference of the Hubble constant and galaxy density profiles
• The Megamaser Cosmology Project. XIII. Combined Hubble constant constraints
• Oscillating scalar fields and the Hubble tension: a resolution with novel signatures
• The Cosmological Constant Problem and Quintessence
• Seven hints that early-time new physics alone is not sufficient to solve the Hubble tension
• The Neutrino Puzzle: Anomalies, Interactions, and Cosmological Tensions
• Early Dark Energy Does Not Restore Cosmological Concordance
• Relic neutrino decoupling with flavour oscillations revisited
• Bounds on very low reheating scenarios after Planck
• Towards a precision calculation of $N_{\mathrm{eff}}$ in the Standard Model II: Neutrino decoupling in the presence of flavour oscillations and finite-temperature QED
• Cosmological implications of ultra-light axion-like fields
• Neutrino decoupling including flavour oscillations and primordial nucleosynthesis
• A precision calculation of the effective number of cosmological neutrinos
• A precision calculation of relic neutrino decoupling
• CBR Anisotropy and the Running of the Scalar Spectral Index
• The Atacama Cosmology Telescope: A Measurement of the Cosmic Microwave Background Power Spectra at 98 and 150 GHz
• Measurements of the E-Mode Polarization and Temperature-E-Mode Correlation of the CMB from SPT-3G 2018 Data
• The Little Rip
• Phenomenological parameterization of quintessence
• Nuclear Reaction Network for Primordial Nucleosynthesis: a detailed analysis of rates, uncertainties and light nuclei yields
• $H_0$ from cosmic chronometers and Type Ia supernovae, with Gaussian Processes and the novel Weighted Polynomial Regression method
• Is the Hubble tension a hint of AdS phase around recombination?
• Constraints on the sum of the neutrino masses in dynamical dark energy models with $w(z)\ge -1$ are tighter than those obtained in $\Lambda$CDM
• Concordance and Discordance in Cosmology
• CMB power spectra and cosmological parameters from Planck PR4 with CamSpec
• Eppur è piatto? The cosmic chronometer take on spatial curvature and cosmic concordance
• Quantifying discordance in the 2015 Planck CMB spectrum
• Analytical treatment of neutrino asymmetry equilibration from flavour oscillations in the early universe
• Early Dark Energy Cosmologies
• The evidence for a spatially flat Universe
• The implications of an extended dark energy cosmology with massive neutrinos for cosmological tensions
• Cosmological parameters derived from the final (PR4) Planck data release
• Revisiting a negative cosmological constant from low-redshift data
• Planck intermediate results. LI. Features in the cosmic microwave background temperature power spectrum and shifts in cosmological parameters
• The Hubble Constant from Infrared Surface Brightness Fluctuation Distances
• Evidence for dark energy from the cosmic microwave background alone using the Atacama Cosmology Telescope lensing measurements
• Updated results on neutrino mass and mass hierarchy from cosmology with Planck 2018 likelihoods
• Investigating Cosmic Discordance
• Rock 'n' Roll Solutions to the Hubble Tension
• Precision calculations of the gravitational wave background spectrum from inflation
• Possible signals of vacuum dynamics in the Universe
• A combined analysis of the $H_0$ late time direct measurements and the impact on the Dark Energy sector
• The Hubble Tension in Light of the Full-Shape Analysis of Large-Scale Structure Data
• Phantom Cosmology without Big Rip Singularity
• Bayesian Inference in Processing Experimental Data: Principles and Basic Applications
• Early dark energy resolution to the Hubble tension in light of weak lensing surveys and lensing anomalies
• KiDS-1000 Cosmology: constraints beyond flat $\Lambda$CDM
• The Atacama Cosmology Telescope: Constraints on Pre-Recombination Early Dark Energy
• New constraint on Early Dark Energy from Planck and BOSS data using the profile likelihood
• The galaxy power spectrum take on spatial curvature and cosmic concordance
• A Detailed Description of the CamSpec Likelihood Pipeline and a Reanalysis of the Planck High Frequency Maps
• Small Magellanic Cloud Cepheids Observed with the Hubble Space Telescope Provide a New Anchor for the SH0ES Distance Ladder
• Cosmicflows 4: The Calibration of Optical and Infrared Tully-Fisher Relations
• Using The Baryonic Tully-Fisher Relation to Measure $H_o$
• Dark Energy at early times and ACT: a larger Hubble constant without late-time priors
• Comparing Tip of the Red Giant Branch Distance Scales: An Independent Reduction of the Carnegie-Chicago Hubble Program and the Value of the Hubble Constant
• Quantifying tensions in cosmological parameters: Interpreting the DES evidence ratio
• Restoring cosmological concordance with early dark energy and massive neutrinos?
• An 8\% Determination of the Hubble Constant from localized Fast Radio Bursts
• Constraints on the curvature of the Universe and dynamical dark energy from the Full-shape and BAO data
• How early is early dark energy?
• Bayesian evidence as a tool for comparing datasets
• Towards a precision calculation of the effective number of neutrinos $N_{\mathrm{eff}}$ in the Standard Model I: The QED equation of state
• Constraints on $\Lambda$CDM Extensions from the SPT-3G 2018 $EE$ and $TE$ Power Spectra
• Implication of the Hubble tension for the primordial Universe in light of recent cosmological data
• Cosmology with the EFTofLSS and BOSS: dark energy constraints and a note on priors
• Cosmic chronometers to calibrate the ladders and measure the curvature of the Universe. A model-independent study
• Assessing tension metrics with Dark Energy Survey and Planck data
• Arguments against using $h^{-1}\mathrm{Mpc}$ units in observational cosmology
• Quantifying the global parameter tensions between ACT, SPT and Planck
• Clustering and Halo Abundances in Early Dark Energy Cosmological Models
• Constraining the time evolution of dark energy, curvature and neutrino properties with cosmic chronometers
• Strong evidence for an accelerating universe
• A 5% measurement of the Hubble constant from Type II supernovae
• Updated constraints from the effective field theory analysis of BOSS power spectrum on Early Dark Energy
• Resolving the Hubble tension with Early Dark Energy
• Soundness of Dark Energy properties
• On the accuracy of time-delay cosmography in the Frontier Fields Cluster MACS J1149.5+2223 with supernova Refsdal
• Inflation and reheating in theories with spontaneous scale invariance symmetry breaking
• Hot New Early Dark Energy
• A double take on early and interacting dark energy from JWST
• A tale of two (or more) $h$'s
• Health checkup test of the standard cosmological model in view of recent Cosmic Microwave Background Anisotropies experiments
• The $H_0$ and ${\sigma }_8$ tensions and the scale invariant spectrum
• Cosmological Results from the RAISIN Survey: Using Type Ia Supernovae in the Near Infrared as a Novel Path to Measure the Dark Energy Equation of State
• Towards hybrid inflation with $n_s=1$ in light of Hubble tension and primordial gravitational waves
• Cosmological constraints on slow-roll inflation: an update
• Constraints on early dark energy from CMB lensing and weak lensing tomography
• Taking Bigger Metropolis Steps by Dragging Fast Variables
• Information Gains from Cosmic Microwave Background Experiments
• Planck confronts large scale structure: methods to quantify discordance
• Bayesian Evidence against Harrison-Zel'dovich spectrum in tension cosmology
• Propagating Speed of Primordial Gravitational Waves
• Inflationary potentials yielding constant scalar perturbation spectral indices
• Is the Harrison-Zel'dovich spectrum coming back? ACT preference for $n_s\sim 1$ and its discordance with Planck
• Return of Harrison-Zeldovich spectrum in light of recent cosmological tensions
• Late-Time constraints on Interacting Dark Energy: Analysis independent of $H_0$, $r_d$ and $M_B$
• Consistency tests in cosmology using relative entropy
• Inflation, the Hubble Tension and Early Dark Energy: an alternative overview
• Reconnaissance with JWST of the J-region Asymptotic Giant Branch in Distance Ladder Galaxies: From Irregular Luminosity Functions to Approximation of the Hubble Constant
• A Bayesian interpretation of inconsistency measures in cosmology
• The Mira Distance to M101 and a 4% Measurement of H0
• Cornering the Planck $A_{lens}$ tension with future CMB data
• Do joint CMB and HST data support a scale invariant spectrum?
• Quantifying the global "CMB tension" between the Atacama Cosmology Telescope and the Planck satellite in extended models of cosmology
• Quantifying Suspiciousness Within Correlated Data Sets
• Constraining the dark energy models using Baryon Acoustic Oscillations: An approach independent of $H_0\cdot r_d$
• Internal Robustness: systematic search for systematic bias in SN Ia data
• Beyond $\Lambda$CDM constraints from the full shape clustering measurements from BOSS and eBOSS
• Towards a reliable calculation of relic radiation from primordial gravitational waves
• Observational constraints on early dark energy
• Cold New Early Dark Energy pulls the trigger on the $H_0$ and $S_8$ tensions: a simultaneous solution to both tensions without new ingredients
• Cosmic Inflation at the Crossroads
• Constraining spatial curvature with large-scale structure
• Inflationary Potential as seen from Different Angles: Model Compatibility from Multiple CMB Missions
• Profiling Cold New Early Dark Energy
• On the consistency of $\Lambda$CDM with CMB measurements in light of the latest Planck, ACT, and SPT data
• What is flat ΛCDM, and may we choose it?
• Tickling the CMB damping tail: scrutinizing the tension between the ACT and SPT experiments
• CMB Anomalies and the Hubble Tension
• No rungs attached: A distance-ladder free determination of the Hubble constant through type II supernova spectral modelling
• Quantifying the tension between cosmological and terrestrial constraints on neutrino masses
• Cosmological constraints on early dark energy from the full shape analysis of eBOSS DR16
• An improved Tully-Fisher estimate of $H_0$
• Probing the inflationary background of gravitational waves from large to small scales
• Higher Order Corrections to the Primordial Gravitational Wave Spectrum and its Impact on Parameter Estimates for Inflation
• Information Gain in Cosmology: From the Discovery of Expansion to Future Surveys
• Status Report on the Chicago-Carnegie Hubble Program (CCHP): Measurement of the Hubble Constant Using the Hubble and James Webb Space Telescopes
• Reconciling early dark energy with a Harrison-Zeldovich spectrum
• Running primordial perturbations: Inflationary Dynamics and Observational Constraints
• Current constraints on early and stressed dark energy models and future 21 cm perspectives
• Testing scale-invariant inflation against cosmological data
• Constraining Cosmic Inflation with Observations: Prospects for 2030
• Vanilla Inflation Predicts Negative Running
• Measuring the spectral running from cosmic microwave background and primordial black holes
• Third-order corrections to the slow-roll expansion: calculation and constraints with Planck, ACT, SPT, and BICEP/Keck
• Primordial power spectra from $k$-inflation with curvature
• How robust are the parameter constraints extending the $\Lambda$CDM model?
• Cosmological data and indications for new physics
• Gravitational particle production and the Hubble tension
• Impact of Low ell's on Large Scale Structure Anomalies
• Scale-invariant inflation
• JWST Validates HST Distance Measurements: Selection of Supernova Subsample Explains Differences in JWST Estimates of Local H0
• Cosmological Spatial Curvature with the Alcock-Paczynski Effect

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• Dynamical Dark Energy Beyond Planck? Constraints from multiple CMB probes, DESI BAO and Type-Ia Supernovae
• Dark energy, spatial curvature, and star formation efficiency from JWST photometric and spectroscopic high-redshift galaxies
• Do JWST reionization (optical depth) puzzle, cosmological tensions, and CMB anomalies imply Harrison-Zel'dovich spectrum?