Fundamental Uncertainty in the BAO Scale from Isocurvature Modes

Abstract

Small fractions of isocurvature perturbations correlated with the dominant adiabatic mode are shown to be a significant primordial systematic for future Baryon Acoustic Oscillation (BAO) surveys, distorting the standard ruler distance by broadening and shifting the peak in the galaxy correlation function. Untreated this systematic leads to biases that can exceed $10\sigma$ in the dark energy parameters even for Planck-level isocurvature constraints. Accounting for the isocurvature modes corrects for this bias but degrades the dark energy figure of merit by at least 50\%. The BAO data in turn provides extremely powerful new constraints on the nature of the primordial perturbations. Future large galaxy surveys will thus be powerful probes of the earliest phase of the universe in addition to helping pin down the nature of dark energy.

arXiv comment5 pages, 3 figures, 1 table

References in corpus (23)

• Exploring the Expansion History of the Universe
• Accelerating Universes with Scaling Dark Matter
• Generating the curvature perturbation without an inflaton
• Probing Dark Energy with Baryonic Acoustic Oscillations from Future Large Galaxy Redshift Surveys
• Probing dark energy using baryonic oscillations in the galaxy power spectrum as a cosmological ruler
• On the Robustness of the Acoustic Scale in the Low-Redshift Clustering of Matter
• Improved forecasts for the baryon acoustic oscillations and cosmological distance scale
• The bispectrum of galaxies from high-redshift galaxy surveys: primordial non-Gaussianity and non-linear galaxy bias
• The General Primordial Cosmic Perturbation
• Isocurvature Perturbations in Multiple Inflationary Models
• Probing dark energy with the shear-ratio geometric test
• Constraining Isocurvature Initial Conditions with WMAP 3-year data
• Constraining Isocurvature Perturbations with CMB Polarization
• Constraints on perfect fluid and scalar field dark energy models from future redshift surveys
• Correlation-consistency cartography of the double inflation landscape
• A Scale-Dependent Power Asymmetry from Isocurvature Perturbations
• Constraints on isocurvature models from the WMAP first-year data
• Testing for double inflation with WMAP
• Constraints on primordial isocurvature perturbations and spatial curvature by Bayesian model selection
• Dynamics of Cosmological Perturbations in Position Space
• Isocurvature modes and Baryon Acoustic Oscillations
• Measuring the geometry of the Universe in the presence of isocurvature modes
• Delayed Recombination and Standard Rulers

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• Baryon Acoustic Oscillation Theory and Modelling Systematics for the DESI 2024 results
• Robustness to systematics for future dark energy probes
• Constraints on scalar and tensor perturbations in phenomenological and two-field inflation models: Bayesian evidences for primordial isocurvature and tensor modes
• Isocurvature perturbations in extra radiation
• On measuring the absolute scale of baryon acoustic oscillations
• Constraints on neutrino density and velocity isocurvature modes from WMAP-9 data
• The sensitivity of BAO Dark Energy Constraints to General Isocurvature Perturbations
• Searching for dark matter isocurvature initial conditions with N-body Simulations