English

Gradient expansion(s) and dark energy

Astrophysics 2009-11-13 v2

Abstract

Motivated by recent claims stating that the acceleration of the present Universe is due to fluctuations with wavelength larger than the Hubble radius, we present a general analysis of various perturbative solutions of fully inhomogeneous Einstein equations supplemented by a perfect fluid. The equivalence of formally different gradient expansions is demonstrated. If the barotropic index vanishes, the deceleration parameter is always positive semi-definite.

Keywords

Cite

@article{arxiv.astro-ph/0506715,
  title  = {Gradient expansion(s) and dark energy},
  author = {Massimo Giovannini},
  journal= {arXiv preprint arXiv:astro-ph/0506715},
  year   = {2009}
}

Comments

17 pages, no figures

R2 v1 2026-07-22T08:53:45.288Z