Observational constraints on braneworld inflation: The effect of a Gauss-Bonnet term

Journal Article · Wed Sep 15 04:00:00 EDT 2004 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PhysRevD.70.063525· OSTI ID:20705217

Tsujikawa, Shinji ^[1]; Sami, M ^[2]; Maartens, Roy ^[3]

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1. Department of Physics, Gunma National College of Technology, Gunma 371-8530 (Japan)
2. IUCAA, Post Bag 4, Ganeshkhind, Pune 411 007 (India)
3. Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 2EG (United Kingdom)

High-energy modifications to general relativity introduce changes to the perturbations generated during inflation, and the latest high-precision cosmological data can be used to place constraints on such modified inflation models. Recently it was shown that Randall-Sundrum-type braneworld inflation leads to tighter constraints on quadratic and quartic potentials than in general relativity. We investigate how this changes with a Gauss-Bonnet correction term, which can be motivated by string theory. Randall-Sundrum models preserve the standard consistency relation between the tensor spectral index and the tensor-to-scalar ratio. The Gauss-Bonnet term breaks this relation, and also modifies the dynamics and perturbation amplitudes at high energies. We find that the Gauss-Bonnet term tends to soften the Randall-Sundrum constraints. The observational compatibility of the quadratic potential is strongly improved. For a broad range of energy scales, the quartic potential is rescued from marginal rejection. Steep inflation driven by an exponential potential is excluded in the Randall-Sundrum case, but the Gauss-Bonnet term leads to marginal compatibility for sufficient e-folds.

• OSTI ID: 20705217
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 6 Vol. 70; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACCURACY
AMPLITUDES
COMPATIBILITY
CORRECTIONS
COSMOLOGY
DISTURBANCES
GENERAL RELATIVITY THEORY
INDEXES
INFLATIONARY UNIVERSE
POTENTIALS
SCALARS
STRING MODELS
TENSORS