2006/09/30 by Christopher Savage, Katherine Freese, William H. Kinney · 1 citation
Physics and Astronomy · #Anisotropy #CMB cold spot #Cosmic microwave background #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Inflation (cosmology) #Inflaton #Lambda #Order (exchange) #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum mechanics #Sensitivity (control systems) #Spectral index #Spectral line #astro-ph #hep-ph
paper · pdf · doi:10.1103/physrevd.74.123511
published as Phys.Rev.D74:123511,2006 · 9 pages, 8 figures. v2: Added references and minor revisions. Submitted to PRD
arxiv created 2006/11/16 · openalex publication_date 2006/12/13 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The model of natural inflation is examined in light of recent 3-year data from the Wilkinson Microwave Anisotropy Probe and shown to provide a good fit. The inflaton potential is naturally flat due to shift symmetries, and in the simplest version takes the form V(\ensuremathφ)=\ensuremathΛ4[1\ifmmode±\else\textpm\ficos(N\ensuremathφ/f)]. The model agrees with WMAP3 measurements as long as f>0.7mPl (where mPl=1.22\ifmmode×\else\texttimes\fi1019 GeV) and \ensuremathΛ\ensuremath∼mGUT. The running of the scalar spectral index is shown to be small---an order of magnitude below the sensitivity of WMAP3. The location of the field in the potential when perturbations on observable scales are produced is examined; for f>5mPl, the relevant part of the potential is indistinguishable from a quadratic, yet has the advantage that the required flatness is well-motivated. Depending on the value of f, the model falls into the large field (f\ensuremath≥1.5mPl) or small field (f<1.5mPl) classification scheme that has been applied to inflation models. Natural inflation provides a good fit to WMAP3 data.