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arXiv · 1909.10805

Oscillon of Ultra-Light Axion-like Particle

Masahiro Kawasaki·Wakutaka Nakano·Eisuke Sonomoto
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Abstract

Ultra-light axion-like particle (ULAP) is one of attractive candidates for cold dark matter. Because the de Broglie wavelength of ULAP with mass $\sim 10^{-22} {\rm eV}$ is $\mathcal{O}({\rm kpc})$, the suppression of the small scale structure by the uncertainty principle can solve the core-cusp problem. Frequently, ULAP is assumed to be uniformly distributed in the present universe. In typical ULAP potentials, however, strong self-resonance at the beginning of oscillation invokes the large fluctuations, which may cause the formation of the dense localized object, oscillon. % Such a dense object lives for a long time, it may affect the cosmological evolution. In this paper, we confirm the oscillon formation in a ULAP potential by numerical simulation and analytically derive its lifetime.

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Masahiro Kawasaki, Wakutaka Nakano, Eisuke Sonomoto. 2019-09-24. Oscillon of Ultra-Light Axion-like Particle. https://doi.org/10.1088/1475-7516%2F2020%2F01%2F047

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