2003/05/19 by Daniel J. H. Chung, Gary Shiu, Mark Trodden · 3 citations
Physics and Astronomy · #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena #astro-ph #hep-ph #hep-th
paper · pdf · doi:10.1103/physrevd.68.063501
published as Phys.Rev. D68 (2003) 063501 · 39 pages, 4 figures, references added
arxiv created 2003/05/19 · openalex publication_date 2003/09/08 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The scalar spectral index n is an important parameter describing the nature of primordial density perturbations. Recent data, including those from the Wilkinson Microwave Anisotropy Probe satellite, show some evidence that the index runs (changes as a function of the scale k at which it is measured) from n>1 (blue) on long scales to n<1 (red) on short scales. We investigate the extent to which inflationary models can accommodate such significant running of n. We present several methods for constructing large classes of potentials which yield a running spectral index. We show that within the slow-roll approximation, the fact that n\ensuremath-1 changes sign from blue to red forces the slope of the potential to reach a minimum at a similar field location. We also briefly survey the running of the index in a wider class of inflationary models, including a subset of those with nonminimal kinetic terms.