Cosmological Tension of Ultralight Axion Dark Matter and its Solutions

Abstract

A number of proposed and ongoing experiments search for axion dark matter with a mass nearing the limit set by small scale structure ($\mathcal{O}(10^{-21}\mathrm{eV})$). We consider the late universe cosmology of these models, showing that requiring the axion to have a matter-power spectrum that matches that of cold dark matter constrains the magnitude of the axion couplings to the visible sector. Comparing these limits to current and future experimental efforts, we find that many searches require axions with an abnormally large coupling to Standard Model fields, independently of how the axion was populated in the early universe. We survey mechanisms that can alleviate the bounds, namely, the introduction of large charges, various forms of kinetic mixing, a clockwork structure, and imposing a discrete symmetry. We provide an explicit model for each case and explore their phenomenology and viability to produce detectable ultralight axion dark matter.

11 pages, 3 figures

References in corpus (18)

• Ultralight scalars as cosmological dark matter
• Discovering the QCD Axion with Black Holes and Gravitational Waves
• Revisiting the SN1987A gamma-ray limit on ultralight axion-like particles
• Lyman-alpha Constraints on Ultralight Scalar Dark Matter: Implications for the Early and Late Universe
• Search for axion-like dark matter through nuclear spin precession in electric and magnetic fields
• Search for axionlike dark matter with a liquid-state nuclear spin comagnetometer
• Microwave Background Constraints on Mixing of Photons with Hidden Photons
• The photo-philic QCD axion
• Pulsar Timing Probes of Primordial Black Holes and Subhalos
• Neutrino Oscillations as a Probe of Light Scalar Dark Matter
• Substructure of fuzzy dark matter haloes
• The impact of ultra-light axion self-interactions on the large scale structure of the Universe
• Heterodyne Broadband Detection of Axion Dark Matter
• Merger of Dark Matter Axion Clumps and Resonant Photon Emission
• Large Field Inflation from Axion Mixing
• Dynamical Clockwork Axions
• Constraining early dark energy with gravitational waves before recombination
• Hidden axion dark matter decaying through mixing with QCD axion and the 3.5 keV X-ray line

Cited by in corpus (18)

• Recent Progress in the Physics of Axions and Axion-Like Particles
• The Cosmic Axion Background
• Dark matter from an even lighter QCD axion: trapped misalignment
• Galactic rotation curves versus ultralight dark matter: A systematic comparison with SPARC data
• Testing the ALP-photon coupling with polarization measurements of Sagittarius A*
• Selective enhancement of the QCD axion couplings
• Electromagnetic Bursts from Mergers of Oscillons in Axion-like Fields
• Dipole Radiation and Beyond from Axion Stars in Electromagnetic Fields
• Gravitational waves and neutrino oscillations in Chern-Simons axion gravity
• Cosmologically Varying Kinetic Mixing
• Searching for dark-matter waves with PPTA and QUIJOTE pulsar polarimetry
• Detecting Axion Dark Matter with Black Hole Polarimetry
• High-Quality Axions from Higher-Form Symmetries in Extra Dimensions
• Enhanced Early Galaxy Formation in JWST from Axion Dark Matter?
• Phenomenology of the companion-axion model: photon couplings
• Axionic Festina Lente
• Constraints on Axions from Cosmic Distance Measurements
• Cosmology of the companion-axion model: dark matter, gravitational waves, and primordial black holes