2013/02/28 by Jinn-Ouk Gong, Misao Sasaki
Physics and Astronomy · #Amplitude #Bispectrum #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Curvature #Galaxies: Formation, Evolution, Phenomena #Inflation (cosmology) #Limit (mathematics) #Non-Gaussianity #Perturbation (astronomy) #Spectral density #Vacuum state #astro-ph.CO #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1088/0264-9381/30/9/095005
(v1) 9 pages, 1 figure; (v2) 10 pages, more clarifications and references, to appear in Classical and Quantum Gravity
arxiv created 2013/03/30 · openalex publication_date 2013/04/11 · arxiv updated 2015/06/12 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We study the general relation between the power spectrum and the squeezed limit of the bispectrum of the comoving curvature perturbation produced during single-field slow-roll inflation when the initial state is a general vacuum. Assuming the scale invariance of the power spectrum, we derive a formula for the squeezed limit of the bispectrum, represented by the parameter f NL , which is not slow-roll suppressed and is found to contain a single free parameter for a given amplitude of the power spectrum. Then, we derive the conditions for achieving a scale-invariant f NL and discuss a few examples.