2004/03/30 by Yun-Song Piao, Yuan‐Zhong Zhang, Yuan-Zhong Zhang · 1 citation
Physics and Astronomy · #Black Holes and Theoretical Physics #Classical mechanics #Cosmology and Gravitation Theories #Einstein #Frame work #Galaxies: Formation, Evolution, Phenomena #Perturbation (astronomy) #Physics #Quantum mechanics #Spectral line #Statistical physics #Theoretical physics #astro-ph
paper · pdf · doi:10.1103/physrevd.70.043516
published as Phys.Rev. D70 (2004) 043516 · 5 pages, 3 eps figures
arxiv created 2004/03/30 · openalex publication_date 2004/08/17 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
In this paper we describe the evolution of various expanding and contracting phases before the ``bounce'' in Einstein frame. Focusing on the case of a single scalar field, in terms of the parameter w of the state equation, four different regions denoting different expanding and contracting phases are pointed out. We discuss possible scenarios generating the nearly scale-invariant spectrum and show that the inflation and other alternative scenarios recently proposed can be placed in different positions of these regions. Our work offers an interesting classification for the primordial perturbation spectra from various phases before the ``bounce,'' which may have important implications for building an early universe scenario embedded in possible high-energy theories.