Does the BICEP2 Observation of Cosmological Tensor Modes Imply an Era of Nearly Planckian Energy Densities?

Abstract

BICEP2 observations, interpreted most simply, suggest an era of inflation with energy densities of order ($10^{16}\mathrm{GeV}{)}^4$, not far below the Planck density. However, models of TeV gravity with large extra dimensions might allow a very different interpretation involving much more modest energy scales. We discuss the viability of inflation in such models, and conclude that existing scenarios do not provide attractive alternatives to single field inflation in four dimensions. Because the detection of tensor modes strengthens our confidence that inflation occurred, it disfavors models of large extra dimensions, at least for the moment.

arXiv comment4 pages, v3: version to appear in JHEP

References in corpus (15)

• A Large Mass Hierarchy from a Small Extra Dimension
• An Alternative to Compactification
• The Hierarchy Problem and New Dimensions at a Millimeter
• New Dimensions at a Millimeter to a Fermi and Superstrings at a TeV
• BICEP2 I: Detection Of B-mode Polarization at Degree Angular Scales
• Modulus Stabilization with Bulk Fields
• What would we learn by detecting a gravitational wave signal in the cosmic microwave background anisotropy?
• Cosmology of One Extra Dimension with Localized Gravity
• A Natural Framework for Chaotic Inflation
• An Ignoble Approach to Large Field Inflation
• Rapid Asymmetric Inflation and Early Cosmology in Theories with Sub-Millimeter Dimensions
• Reconciliation of High Energy Scale Models of Inflation with Planck
• Extra Dimensions and Inflation
• A Note on Brane Inflation
• Late Inflation and the Moduli Problem of Sub-Millimeter Dimensions

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