Collapse of axion stars

Eby, Joshua; Leembruggen, Madelyn; Surányi, P.; Wijewardhana, L. C. R.

doi:10.1007/jhep12(2016)066

Cited by 117 publications

(197 citation statements)

References 57 publications

(115 reference statements)

Supporting

Mentioning

192

Contrasting

Order By: Relevance

“…The dense branch satisfies (15) for all masses. Similar results were reported in [83] and very recently additional dense branches have been found in [84]. The radii on these branches and at small f can be even closer to the black hole radius.…”

Section: Axionssupporting

confidence: 89%

A conjecture on the minimal size of bound states

et al. 2020

View full text Add to dashboard Cite

We conjecture that, in a renormalizable effective quantum field theory where the heaviest stable particle has mass m , there are no bound states with radius below 1/m (Bound State Conjecture). We are motivated by the (scalar) Weak Gravity Conjecture, which can be read as a statement forbidding certain bound states. As we discuss, versions for uncharged particles and their generalizations have shortcomings.This leads us to the suggestion that one should only constrain rather than exclude bound objects. In the gravitational case, the resulting conjecture takes the sharp form of forbidding the adiabatic construction of black holes smaller than 1/m . But this minimal bound-state radius remains non-trivial as M P → ∞ , leading us to suspect a feature of QFT rather than a quantum gravity constraint. We find support in a number of examples which we analyze at a parametric level.

show abstract

Section: Axionssupporting

confidence: 89%

A conjecture on the minimal size of bound states

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Numerous fascinating, potentially observable phenomena involving axion star collapse, decay, or collisions with other astrophysical objects have been proposed in the literature [216,217,218,219,220,221,222,223,224,225,226,227]. Involving relativistic effects, self-interactions, or axion-photon coupling in fundamental ways, they unfortunately extend beyond the self-imposed scope of this article.…”

Section: Formation Of Axion Starsmentioning

confidence: 99%

Small-scale structure of fuzzy and axion-like dark matter

Niemeyer

2020

Progress in Particle and Nuclear Physics

161

View full text Add to dashboard Cite

Axion-like particle (ALP) dark matter shows distinctive behavior on scales where wavelike effects dominate over self-gravity. Ultralight axions are candidates for fuzzy dark matter (FDM) whose de Broglie wavelength in virialized halos reaches scales of kiloparsecs. Important features of FDM scenarios are the formation of solitonic halo cores, suppressed small-scale perturbations, and enhanced gravitational relaxation. More massive ALPs, including the QCD axion, behave like CDM on galactic scales but may be clumped into axion miniclusters if they were produced after inflation. Just as FDM halos, axion miniclusters may host the formation of coherent bound objects (axion stars) by Bose-Einstein condensation. This article presents a selection of topics in this field that are currently under active investigation.

show abstract

“…For clarity, we note that Eq. (III.8) is equivalent to the standard GP equation used to analyze axion stars [21,30]. This is made transparent by identifying, as in [29], the relationship between Z(y) and the standard Schrödinger wavefunction ψ:…”

Section: Gross-pitaevskii-poisson (Gpp)mentioning

confidence: 99%

“…A recent surge in studies of boson stars [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] stems, in part, from the renewed interest in determining whether dark matter (DM) could consist of condensates of ax-ions or other axion like particles. A particularly wellmotivated scalar DM candidate is the QCD axion, parametrized by a decay constant f = 6 × 10 11 GeV and particle mass m = 10 −5 eV; 2 as a result, bound states of QCD axions (which we will call QCD axion stars) have received special attention.…”

Section: Introductionmentioning

confidence: 99%

“…The solutions found by BB for QCD axion stars fall in the range of transition axion star solutions which, as it turns out, are structurally unstable to collapse, as they correspond to a maximum rather than a minimum of the energy functional. Collapsing axion stars evaporate a large fraction of their mass through rapid emission of relativistic axions [21,23,[32][33][34].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Global view of QCD axion stars

et al. 2019

Self Cite

View full text Add to dashboard Cite

Taking a comprehensive view, including a full range of boundary conditions, we reexamine QCD axion star solutions based on the relativistic Klein-Gordon equation (using the Ruffini-Bonazzola approach) and its non-relativistic limit, the Gross-Pitaevskii equation. A single free parameter, conveniently chosen as the central value of the wavefunction of the axion star, or alternatively the chemical potential with range −m < µ < 0 (where m is the axion mass), uniquely determines a spherically-symmetric ground state solution, the axion condensate. We clarify how the interplay of various terms of the Klein-Gordon equation determines the properties of solutions in three separate regions: the structurally stable (corresponding to a local energy minimum) dilute and dense regions, and the intermediate, structurally unstable transition region. From the Klein-Gordon equation, one can derive alternative equations of motion including the Gross-Pitaevskii and Sine-Gordon equations, which have been used previously to describe axion stars in the dense region. In this work, we clarify precisely how and why such methods break down as the binding energy increases, emphasizing the necessity of using the full relativistic Klein-Gordon approach. Finally, we point out that, even after including perturbative axion number violating corrections, solutions to the equations of motion, which assume approximate conservation of axion number, break down completely in the regime with strong binding energy, where the magnitude of the chemical potential approaches the axion mass.

show abstract

Collapse of axion stars

Cited by 117 publications

References 57 publications

A conjecture on the minimal size of bound states

A conjecture on the minimal size of bound states

Small-scale structure of fuzzy and axion-like dark matter

Global view of QCD axion stars

Contact Info

Product

Resources

About