2005/12/31 by Masahide Yamaguchi, Jun’ichi Yokoyama, Jun'ichi Yokoyama · 1 citation
Mathematics · Physics and Astronomy · #Black Holes and Theoretical Physics #Classical mechanics #Cosmology and Gravitation Theories #Curvature #Field (mathematics) #Formalism (music) #Galaxies: Formation, Evolution, Phenomena #Geometry #Inflation (cosmology) #Inflaton #Mathematical analysis #Mathematics #Maxima and minima #Physics #Quantum electrodynamics #Quantum mechanics #Statistical physics #Theoretical physics #Universe #astro-ph #hep-ph
paper · pdf · doi:10.1103/physrevd.74.043523
published as Phys.Rev. D74 (2006) 043523 · 9 pages, to appear in Phys. Rev. D
arxiv created 2006/08/09 · openalex publication_date 2006/08/17 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Any one-field inflation is actually realized in a multifield configuration because the inflaton must have couplings with other fields to reheat the universe and is coupled to all other fields at least gravitationally. In all single inflaton models, it is explicitly or implicitly assumed that the heavier fields are stuck to their potential minima during inflation, which are time-dependent in general. We present a formalism to calculate curvature perturbations in such a time-dependent background and show that the proper expression can be obtained using a single-field analysis with a reduced potential in which all these heavy fields are situated at their respective, time-dependent minima. Our results provide a firm ground on the conventional calculation.