2007/06/30 by Yun-Song Piao
Mathematics · Physics and Astronomy · #Black Holes and Theoretical Physics #Classical mechanics #Cosmology #Cosmology and Gravitation Theories #Curvature #Galaxies: Formation, Evolution, Phenomena #Geometry #Mathematical physics #Mathematics #Observable #Observable universe #Perturbation (astronomy) #Phase transition #Physics #Quantum mechanics #gr-qc
paper · pdf · doi:10.1103/physrevd.76.083505
published as Phys.Rev.D76:083505,2007 · 5 pages, 1 eps figure, minor changes and refs. added, to publish in PRD
arxiv created 2007/08/20 · openalex publication_date 2007/10/08 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Recently, it has been shown that a slow expansion, which is asymptotically a static state in infinite past and may be described as an evolution with ϵ\ensuremath≪\ensuremath-1, of early universe may lead to the generation of primordial perturbation responsible for the structure formation of observable universe. However, its feasibility depends on whether the growing mode of Bardeen potential before phase transition can be inherited by the constant mode of curvature perturbation after phase transition. In this paper, we phenomenally regard this slow expansion as that driven by multi-NEC (null energy condition) violating scalar fields. We calculate the curvature perturbation induced by the entropy perturbation before phase transition and find that the spectrum is naturally scale invariant with a slight red tilt. The result has an interesting similarity to that of slow roll inflation.