Oscillon of ultra-light axion-like particle

Ultra-Light axion-like particle (ULAP) is one of the attractive candidates for cold dark matter. Because the de Broglie wavelength of ULAP with mass $\sim {10}^{-22}eV$ is $O\left(kpc\right)$, 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. In this paper, we confirm the oscillon formation in a ULAP potential by numerical simulation and analytically derive its lifetime.