Non-Gaussianity in Axion N-flation Models

Journal Article · Fri Oct 29 04:00:00 EDT 2010 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.105.181302· OSTI ID:21467046

Kim, Soo A ^[1]; Liddle, Andrew R; Seery, David ^[2]

---

1. Department of Astronomy and Space Science, Kyung Hee University, Yong-in 446-701 (Korea, Republic of)
2. Astronomy Centre, University of Sussex, Brighton BN1 9QH (United Kingdom)

We study perturbations in the multifield axion N-flation model, taking account of the full cosine potential. We find significant differences from previous analyses which made a quadratic approximation to the potential. The tensor-to-scalar ratio and the scalar spectral index move to lower values, which nevertheless provide an acceptable fit to observation. Most significantly, we find that the bispectrum non-Gaussianity parameter f{sub NL} may be large, typically of order 10 for moderate values of the axion decay constant, increasing to of order 100 for decay constants slightly smaller than the Planck scale. Such a non-Gaussian fraction is detectable. We argue that this property is generic in multifield models of hilltop inflation.

• OSTI ID: 21467046
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 18 Vol. 105; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
79 ASTRONOMY AND ASTROPHYSICS
APPROXIMATIONS
AXIONS
BOSONS
CALCULATION METHODS
COSMOLOGICAL MODELS
COSMOLOGY
DECAY
DISTURBANCES
DOCUMENT TYPES
ELEMENTARY PARTICLES
GOLDSTONE BOSONS
INDEXES
INFLATIONARY UNIVERSE
MATHEMATICAL MODELS
PARTICLE DECAY
POSTULATED PARTICLES
POTENTIALS
SCALARS
TENSORS