1993/10/06 by Katherine Freese, Freese, Katherine · 3 citations
Physics and Astronomy · #Astrophysics (astro-ph) #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #FOS: Physical sciences #Particle physics theoretical and experimental studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9310012
10 pages, plain tex
arxiv created 1993/10/06 · openalex publication_date 1993/10/06 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A pseudo-Nambu-Goldstone boson, with a potential of the form V(ϕ) = Λ4 [1 + cos(ϕ/f)], can naturally give rise to an epoch of inflation in the early universe (Freese, Frieman, and Olinto 1990). The potential is naturally flat (as required by microwave background limits on the amplitude of density fluctuations), without any fine-tuning. Successful inflation can be achieved if f ∼ mpl and Λ∼ mGUT. Such mass scales arise in particle physics models with a large gauge group that becomes strongly interacting at a scale ∼ Λ, \it e.g., as can happen in the hidden sector of superstring theories. The density fluctuation spectrum can be non-scale-invariant, with more power on large length scales (Adams, Bond, Freese, Frieman, and Olinto 1993). This enhanced power on large scales may be useful to explain the otherwise puzzling large-scale clustering of galaxies and clusters and their flows. Natural inflation differs from other models with extra large-scale power in that the contribution of the tensor modes to microwave background fluctuations is negligible; this difference should serve as a testable feature of the model.