Derives the power spectrum evolution and cross-spectra for arbitrary multi-species wave and particle dark matter, incorporating free-streaming, Jeans scales, and intrinsic fluctuations.
Early seeds of axion miniclusters
7 Pith papers cite this work. Polarity classification is still indexing.
7
Pith papers citing it
abstract
We study the small scale structure of axion dark matter in the post-inflationary scenario, which predicts the formation of low-mass, high-density clumps of gravitationally bound axions called axion miniclusters. To this end, we follow numerically the cosmological evolution of the axion field and the network of strings and domain walls until the density contrast is frozen. Our simulations, comprising up to $8192^3$ points, are the largest studies of the axion field evolution in the non-linear regime presented so far. Axitons, pseudo-breathers of the Klein-Gordon equation, are observed to form in our simulation at late times. Studying their properties analytically and numerically, we observe that in particular, the earliest axitons contribute to density perturbations at the typical length scale of miniclusters. We analyse the small scale structure of the density field, giving the correlation length, power spectrum and the distribution of high-density regions that will collapse into axion miniclusters. The final density field of our simulations can be used to calculate the minicluster mass fraction in simulations including gravity. In particular, we find that typical minicluster progenitors are smaller than previously thought and only of moderate, $\mathcal{O}(1)$ overdensity. We expect these miniclusters to have a rich sub-structure, emerging from small-scale fluctuations produced in the collapse of the string-wall network and from axitons.
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Pre-inflationary QCD axions form dense stars with densities up to 10^4 eV^4 that contain up to 50% of dark matter after moduli domination.
Multi-field oscillons in the Friedberg-Lee-Sirlin model form bound states of two co-located oscillons that oscillate at their respective masses due to attractive interactions.
Small explicit Peccei-Quinn breaking introduces a mass scale μ that can dominate early axion dynamics, causing the string-wall network to annihilate earlier and making relic abundance depend on both μ and f_a rather than f_a alone.
Axion stars in miniclusters can reach bosenova conditions within the age of the Universe for QCD axions when initial overdensity exceeds roughly 100, once self-interaction effects are included.
A mini-review of axion phenomenology showing how light bosons can account for dark matter, drive cosmic acceleration, or contribute to relativistic backgrounds in the early and late Universe.
Review classifies QCD axion models extending the standard mass-coupling window and updates bounds from cosmology, astrophysics, and experiments.
citing papers explorer
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Growth of Structure in Multi-species Wave Dark Matter
Derives the power spectrum evolution and cross-spectra for arbitrary multi-species wave and particle dark matter, incorporating free-streaming, Jeans scales, and intrinsic fluctuations.
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Pre-inflationary QCD axion stars after moduli domination
Pre-inflationary QCD axions form dense stars with densities up to 10^4 eV^4 that contain up to 50% of dark matter after moduli domination.
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Multi-field oscillons/I-balls in the Friedberg-Lee-Sirlin model
Multi-field oscillons in the Friedberg-Lee-Sirlin model form bound states of two co-located oscillons that oscillate at their respective masses due to attractive interactions.
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On the predictivity of axion dark matter in the presence of Peccei-Quinn breaking
Small explicit Peccei-Quinn breaking introduces a mass scale μ that can dominate early axion dynamics, causing the string-wall network to annihilate earlier and making relic abundance depend on both μ and f_a rather than f_a alone.
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Axion Star Bosenova in Axion Miniclusters
Axion stars in miniclusters can reach bosenova conditions within the age of the Universe for QCD axions when initial overdensity exceeds roughly 100, once self-interaction effects are included.
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Axions as Dark Matter, Dark Energy, and Dark Radiation
A mini-review of axion phenomenology showing how light bosons can account for dark matter, drive cosmic acceleration, or contribute to relativistic backgrounds in the early and late Universe.
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The landscape of QCD axion models
Review classifies QCD axion models extending the standard mass-coupling window and updates bounds from cosmology, astrophysics, and experiments.