Back to Search
Start Over
Cosmological Perturbations of Extreme Axion in the Radiation Era
- Publication Year :
- 2017
-
Abstract
- Sub-horizon perturbations under the extreme initial condition of the axion model are investigated, where initial axion angles start near the potential maximum. This work focuses on a few new features found in the extreme axion model but absent in the free-particle model. A particularly novel new feature is the spectral excess relative to the CDM model in some wave number range, where the excess may be so large that landscapes of high-redshift universe beyond $z=10$ can be significantly altered. For axions of particle mass $10^{-22}$ eV, this range of wave number corresponds to first galaxies of few times $10^9-10^{10} M_\odot$. We demonstrate that sub-horizon perturbations are accurately described by Mathieu's equation and subject to parametric instability, which explains this novel feature. Actually the axion model is not a special one; perturbations in a wide range of scalar field models can share the similar characteristic.<br />11 pages, 3 figures
- Subjects :
- Physics
Particle physics
Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Cold dark matter
010308 nuclear & particles physics
Oscillation
media_common.quotation_subject
FOS: Physical sciences
01 natural sciences
Galaxy
Universe
0103 physical sciences
Initial value problem
Boundary value problem
010303 astronomy & astrophysics
Scalar field
Axion
media_common
Astrophysics - Cosmology and Nongalactic Astrophysics
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....fc2327f6de5888ce27b2fcfb9ddf7753