Year: 2007
Type: article
Abstract: 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 $ϵ\ensuremath{\ll}\ensuremath{-}1$, 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.
Author: Yun-Song Piao
Institution: Chinese Academy of Sciences
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2069420394