Inflation with Gauss-Bonnet coupling
Apr 24, 2018
12 pages
Published in:
- Phys.Rev.D 98 (2018) 8, 083521
- Published: Oct 17, 2018
e-Print:
- 1804.09116 [gr-qc]
DOI:
- 10.1103/PhysRevD.98.083521 (publication)
View in:
Citations per year
Abstract: (APS)
We consider inflationary models with the inflaton coupled to the Gauss-Bonnet term assuming a special relation δ1=2λε1 between the two slow-roll parameters δ1 and ε1. For the slow-roll inflation, the assumed relation leads to the reciprocal relation between the Gauss-Bonnet coupling function ξ(ϕ) and the potential V(ϕ), and it leads to the relation r=16(1-λ)ε1 that reduces the tensor-to-scalar ratio r by a factor of 1-λ. For the constant-roll inflation, we derive the analytical expressions for the scalar and tensor power spectra, the scalar and tensor spectral tilts, and the tensor-to-scalar ratio to the first order of ε1 by using the method of Bessel function approximation. The tensor-to-scalar ratio is reduced by a factor of 1-λ+λη˜. Comparing the derived ns-r with the observations, we obtain the constraints on the model parameters η˜ and λ.Note:
- 26 pages, 7 figures, major changes, conclusion remains unchanged, PRD in press
- Cosmology
- inflation: slow-roll approximation
- inflation: model
- power spectrum: tensor
- inflaton: coupling
- Gauss-Bonnet term
- cosmological model
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Figures(8)
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