English

Adiabatic CMB perturbations in pre-big bang string cosmology

High Energy Physics - Phenomenology 2009-11-07 v3 Astrophysics High Energy Physics - Theory

Abstract

We consider the pre-big bang scenario with a massive axion field which starts to dominate energy density when oscillating in an instanton-induced potential and subsequently reheats the universe as it decays into photons, thus creating adiabatic CMB perturbations. We find that the fluctuations in the axion field can give rise to a nearly flat spectrum of adiabatic perturbations with a spectral tilt Δn\Delta n in the range 0.1Δn1-0.1 \lesssim \Delta n \lesssim 1.

Keywords

Cite

@article{arxiv.hep-ph/0109214,
  title  = {Adiabatic CMB perturbations in pre-big bang string cosmology},
  author = {Kari Enqvist and Martin S. Sloth},
  journal= {arXiv preprint arXiv:hep-ph/0109214},
  year   = {2009}
}

Comments

15 pages, 1 figure; Version to appear in Nucl.Phys.B. Figure improved, discussion and one reference added

R2 v1 2026-07-22T13:36:22.267Z