Oscillons of Axion-Like Particle: Mass distribution and power spectrum

Abstract

In string theory, the simultaneous existence of many Axion-Like Particles (ALPs) are suggested over a vast mass range, and a variety of potentials have been developed in the context of inflation. In such potentials shallower than quadratic, the prominent instability can produce localized dense objects, oscillons. Because of the approximate conservation of their adiabatic invariant, oscillons generally survive quite long, maybe up to the current age of the universe in the case of ultra-light ALPs with $m\sim 10^{-22}\mathrm{eV}$. Such oscillons can have significant effects on the evolution of the recent universe. In this paper, we investigate the oscillons of the pure-natural type potential by classical lattice simulation to explore the key quantities necessary for phenomenological application: the number density of oscillons, the oscillon mass distribution, the energy ratio of oscillons to the ALP field, and the power spectrum. Then, we evolve these values in consideration of the analytic decay rate.

18 pages, 10 figures

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Cited by in corpus (9)

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• Beyond Schrödinger-Poisson: Nonrelativistic Effective Field Theory for Scalar Dark Matter
• Recipes for Oscillon Longevity
• Gravitational effects on oscillon lifetimes
• ALP dark matter with non-periodic potentials: parametric resonance, halo formation and gravitational signatures
• Probing Oscillons of Ultra-Light Axion-like Particle by 21cm Forest
• Anisotropies in Cosmological 21 cm Background by Oscillons/I-balls of Ultra-light Axion-like Particle
• Decay and lifetime of oscillons coupled to an external scalar field: Insights from instability band analysis
• Gravitational redshift from large-scale structure: nonlinearities, antisymmetries, and the dipole