Isocurvature forecast in the anthropic axion window

Abstract

We explore the cosmological sensitivity to the amplitude of isocurvature fluctuations that would be caused by axions in the "anthropic window" where the axion decay constant f_a >> 10^12 GeV and the initial misalignment angle Theta_i << 1. In a minimal Lambda-CDM cosmology extended with subdominant scale-invariant isocurvature fluctuations, existing data constrain the isocurvature fraction to alpha < 0.09 at 95% C.L. If no signal shows up, Planck can improve this constraint to 0.042 while an ultimate CMB probe limited only by cosmic variance in both temperature and E-polarisation can reach 0.017, about a factor of five better than the current limit. In the parameter space of f_a and H_I (Hubble parameter during inflation) we identify a small region where axion detection remains within the reach of realistic cosmological probes.

14 pages, 4 figures; v2: matches published version

References in corpus (12)

• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Improved Cosmological Constraints from New, Old and Combined Supernova Datasets
• Cosmological Constraints from the SDSS Luminous Red Galaxies
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Angular Power Spectra
• Probing cosmological parameters with the CMB: Forecasts from full Monte Carlo simulations
• Probing eV-scale axions with CAST
• Update of axion CDM energy density
• Isocurvature bounds on axions revisited
• Axion isocurvature fluctuations with extremely blue spectrum
• An improved cosmological bound on the thermal axion mass
• Inflationary Axion Cosmology Beyond Our Horizon

Cited by in corpus (47)

• Planck 2013 results. XXII. Constraints on inflation
• WISPy Cold Dark Matter
• The QCD axion, precisely
• Axion dark matter from topological defects
• Axion Cosmology Revisited
• Standard Model-Axion-Seesaw-Higgs Portal Inflation. Five problems of particle physics and cosmology solved in one stroke
• An M Theory Solution to the Strong CP Problem and Constraints on the Axiverse
• The Stochastic Axion Scenario
• The Quest for an Intermediate-Scale Accidental Axion and Further ALPs
• Axion cold dark matter in non-standard cosmologies
• The Effective Field Theory of Dark Matter and Structure Formation: Semi-Analytical Results
• A Scale-Dependent Power Asymmetry from Isocurvature Perturbations
• Sub-eV scalar dark matter through the super-renormalizable Higgs portal
• Radio Signal of Axion-Photon Conversion in Neutron Stars: A Ray Tracing Analysis
• Tensor Detection Severely Constrains Axion Dark Matter
• Looking at the NANOGrav Signal Through the Anthropic Window of Axion-Like Particles
• Axion Predictions in $SO(10)\times U(1{)}_{\mathrm{PQ}}$ Models
• Unifying inflation and dark matter with the Peccei-Quinn field: observable axions and observable tensors
• Constraints on ultra-light axions from compact binary systems
• Constraints on primordial isocurvature perturbations and spatial curvature by Bayesian model selection
• Cosmological Axion and Quark Nugget Dark Matter Model
• Axion Dark Matter and Planck favor non-minimal couplings to gravity
• Axions in gravity with torsion
• Future cosmological sensitivity for hot dark matter axions
• Axion mass prediction from minimal grand unification
• Axiverse cosmology and the energy scale of inflation
• A solution of the strong CP problem via the Peccei-Quinn mechanism through the Nieh-Yan modified gravity and cosmological implications
• Axions, Inflation and the Anthropic Principle
• Isocurvature bounds on axion-like particle dark matter in the post-inflationary scenario
• Axion Isocurvature Perturbations in Low-Scale Models of Hybrid Inflation
• Post-inflationary axion isocurvature perturbations facing CMB and large-scale structure
• Constraints on axionic fuzzy dark matter from light bending and Shapiro time delay
• Searching for blue in the dark
• Cosmological limits on axions and axion-like particles
• Minimal solution to the axion isocurvature problem from a nonminimal coupling
• Pati-Salam Axion
• Constraints on monopole-dipole potential from the tests of gravity
• Axion production from primordial magnetic fields
• Isocurvature modes: joint analysis of the CMB power spectrum and bispectrum
• Parametric-Resonance Production of QCD Axions
• Axions in Cold Dark Matter and Inflation Models
• Wormhole-Induced ALP Dark Matter
• Ultralight Dark Matter from the Edge of Field Space
• $F$-term Multi-Field Inflation in Supergravity without Stabiliser Superfields
• Generalized neutrino isocurvature
• An Analytic Treatment of Underdamped Axionic Blue Isocurvature Perturbations
• Stochastic isocurvature constraints for axion dark matter with high-scale inflation