Axion minivoids and implications for direct detection

Eggemeier, Benedikt; O’Hare, Ciaran A. J.; Pierobon, Giovanni; Redondo, Javier; Wong, Yvonne Y. Y.

doi:10.1103/physrevd.107.083510

Cited by 21 publications

(8 citation statements)

References 134 publications

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“…The resulting clumps of axions are expected to have densities comparable to the average dark matter density at the time of formation, roughly eV 4 , which is substantially larger than the present-day dark matter density in the vicinity of the Sun. Such substructure has been studied extensively both by analytical approaches and, most commonly, numerically [18][19][20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

More axions from strings

2021

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We study the contribution to the QCD axion dark matter abundance that is produced by string defects during the so-called scaling regime. Clear evidence of scaling violations is found, the most conservative extrapolation of which strongly suggests a large number of axions from strings. In this regime, nonlinearities at around the QCD scale are shown to play an important role in determining the final abundance. The overall result is a lower bound on the QCD axion mass in the post-inflationary scenario that is substantially stronger than the naive one from misalignment.

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Section: Introductionmentioning

confidence: 99%

More axions from strings

2021

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“…Axion cosmology Ciaran A. J. O'Hare Figure 13: Snapshot of some merging axion miniclusters in the N-body simulations performed for Ref. [165]. The redshift of the snapshot is 𝑧 = 999, so well before the formation of galaxies.…”

Section: Pos(cosmicwispers)040 Pos(cosmicwispers)040mentioning

confidence: 99%

“…It is not particularly enlightening to go through these disagreements; ultimately, they are just estimates. We will get a more complete picture by doing gravitational simulations [165,[178][179][180][181][182], as I will get to shortly.…”

Section: Pos(cosmicwispers)040 Pos(cosmicwispers)040mentioning

confidence: 99%

“…[171,172,176,177,184,185]. However, for this next stage of evolution, a better way to get a handle on the non-linear growth of miniclusters, their mergers into minicluster halos, as well as their internal structures, is to perform N-body simulations [165,[178][179][180]182]. 29 N-body simulations, as the name suggests are simulations in which the gravitational attraction of 𝑁 particles on each other is evolved through cosmic time.…”

Section: Pos(cosmicwispers)040 Pos(cosmicwispers)040mentioning

confidence: 99%

“…29 N-body simulations, as the name suggests are simulations in which the gravitational attraction of 𝑁 particles on each other is evolved through cosmic time. There are now a handful of studies in the literature which have performed N-body simulations of miniclusters, starting either from an initial power spectrum left over from early-Universe lattice simulations [165,178,181,182] or from white noise [179]. To do the former type of simulations, fluctuations in the density of the continuous axion field are mapped into discrete particles.…”

Section: Pos(cosmicwispers)040 Pos(cosmicwispers)040mentioning

confidence: 99%

See 2 more Smart Citations

Cosmology of axion dark matter

O'Hare

2024

Proceedings of 1st General Meeting and 1st Training School of the COST Action COSMIC WSIPers — PoS(COSMICWISPers)

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I present an introduction and topical review on axions as a dark matter candidate. Emphasis is placed on issues surrounding the cosmology of axion dark matter that are relevant for presentday searches, including: early-Universe production mechanisms, predictions of the axion mass, bounds on axion properties derived from cosmological data, as well as the direct and indirect detection of relic axion populations.

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Post-inflationary axions: a minimal target for axion haloscopes

Gorghetto

Hardy

2023

J. High Energ. Phys.

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An axion-like-particle (ALP) in the post-inflationary scenario with domain wall number N > 1 can be dark matter if the residual ℤN symmetry has a small explicit breaking. Although we cannot determine the full dynamics of the system reliably, we provide evidence that such an ALP can account for the observed dark matter abundance while having a relatively small decay constant and consequently a possibly large coupling to photons. In particular, we determine the number of domain walls per Hubble patch around the time when they form using numerical simulations and combine this with analytic expectations about the subsequent dynamics. We show that the strongest constraint on the decay constant is likely to come from the dark matter ALPs being produced with large isocurvature fluctuations at small spatial scales. We also comment on the uncertainties on the dark matter small-scale structure that might form from these overdensities, in particular pointing out the importance of quantum pressure in the N = 1 case.

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Axion minivoids and implications for direct detection

Cited by 21 publications

References 134 publications

More axions from strings

More axions from strings

Cosmology of axion dark matter

Post-inflationary axions: a minimal target for axion haloscopes

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