Cosmological perturbations of axion with a dynamical decay constant

Journal Article · Thu Aug 25 04:00:00 EDT 2016 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2016/08/056· OSTI ID:22572138

Kobayashi, Takeshi ^[1]; Takahashi, Fuminobu ^[2]

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1. SISSA,Via Bonomea 265, 34136 Trieste (Italy)
2. Department of Physics, Tohoku University,Sendai, Miyagi 980-8578 (Japan)

A QCD axion with a time-dependent decay constant has been known to be able to accommodate high-scale inflation without producing topological defects or too large isocurvature perturbations on CMB scales. We point out that a dynamical decay constant also has the effect of enhancing the small-scale axion isocurvature perturbations. The enhanced axion perturbations can even exceed the periodicity of the axion potential, and thus lead to the formation of axionic domain walls. Unlike the well-studied axionic walls, the walls produced from the enhanced perturbations are not bounded by cosmic strings, and thus would overclose the universe independently of the number of degenerate vacua along the axion potential.

• Sponsoring Organization: SCOAP3, CERN, Geneva (Switzerland)
• OSTI ID: 22572138
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 08 Vol. 2016; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
AXIONS
COSMOLOGICAL INFLATION
DISTURBANCES
INFLATIONARY UNIVERSE
PARTICLE DECAY
PERTURBATION THEORY
POTENTIALS
QUANTUM CHROMODYNAMICS
RELICT RADIATION
STRING THEORY
TIME DEPENDENCE
VACUUM STATES