Isocurvature constraints and anharmonic effects on QCD axion dark matter

Journal Article · Sun Sep 01 04:00:00 EDT 2013 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2013/09/032· OSTI ID:22282648

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

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1. Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 3H8 (Canada)
2. Department of Physics, Tohoku University, Sendai 980-8578 (Japan)

We revisit the isocurvature density perturbations induced by quantum fluctuations of the axion field by extending a recently developed analytic method and approximations to a time-dependent scalar potential, which enables us to follow the evolution of the axion until it starts to oscillate. We find that, as the initial misalignment angle approaches the hilltop of the potential, the isocurvature perturbations become significantly enhanced, while the non-Gaussianity parameter increases slowly but surely. As a result, the isocurvature constraint on the inflation scale is tightened as H{sub inf}∼

• OSTI ID: 22282648
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 09 Vol. 2013; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
APPROXIMATIONS
AXIONS
DENSITY
ENERGY SPECTRA
FLUCTUATIONS
GEV RANGE
INFLATIONARY UNIVERSE
INFLATONS
LIMITING VALUES
NONLUMINOUS MATTER
PERTURBATION THEORY
POTENTIALS
QUANTUM CHROMODYNAMICS
SCALARS
TIME DEPENDENCE