2005/07/31 by Latham A. Boyle, Paul J. Steinhardt, Neil Turok · 2 citations
Earth and Planetary Sciences · Physics and Astronomy · #Cosmology and Gravitation Theories #Geophysics and Gravity Measurements #Solar and Space Plasma Dynamics #astro-ph #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1103/physrevlett.96.111301
published as Phys.Rev.Lett.96:111301,2006 · 4 pages, 2 figures; references updated; version accepted for publication in PRL
arxiv created 2006/03/22 · openalex publication_date 2006/03/24 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We reconsider the predictions of inflation for the spectral index of scalar (energy density) fluctuations (ns) and the tensor/scalar ratio (r) using a discrete, model-independent measure of the degree of fine-tuning required to obtain a given combination of (ns, r ). We find that, except for cases with numerous unnecessary degrees of fine-tuning, ns is less than 0.98, measurably different from exact Harrison-Zel'dovich. Furthermore, if ns >or= 0.95, in accord with current measurements, the tensor/scalar ratio satisfies r >or= 10(-2), a range that should be detectable in proposed cosmic microwave background polarization experiments and direct gravitational wave searches.