2015/07/31 by Takehiko Asaka, T. Asaka, Satoshi Iso +5 · 2 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Compactification (mathematics) #Cosmology and Gravitation Theories #Einstein #Inflation (cosmology) #Lambda #Mathematical physics #Physics #Planck #Planck scale #Pure mathematics #Quantum #Quantum gravity #Quantum mechanics #Reinterpretation #Relativity and Gravitational Theory #Spectral index #Spectral line #Theoretical physics #astro-ph.CO #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1093/ptep/ptw161
published as Prog. Theor. Exp. Phys. 2016, 123E01 · 13 pages, 2 figures; published version, references and discussion on the uncertainties of the predictions added
openalex publication_date 2016/10/11 · arxiv created 2016/10/30 · arxiv updated 2016/12/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The Starobinsky model of inflation, consistent with Planck 2015, has a peculiar form of the action, which contains the leading Einstein term R, the R2 term with a huge coefficient, and negligible higher-order terms. We propose an explanation of this form based on compactification of extra dimensions. Once tuning of order 10−4 is accepted to suppress the linear term R, we no longer have to suppress higher-order terms, which give nontrivial corrections to the Starobinsky model. We show our predictions of the spectral index, its runnings, and the tensor-to-scalar ratio. Finally, we discuss a possibility that quantum gravity may appear at the scale Λ≳5×1015 GeV.