Matter instabilities in general Gauss-Bonnet gravity

Antonio De Felice, David F. Mota, Shinji Tsujikawa

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We study the evolution of cosmological perturbations in f(G) gravity, where the Lagrangian is the sum of a Ricci scalar R and an arbitrary function f in terms of a Gauss-Bonnet term G. We derive the equations for perturbations assuming matter to be described by a perfect fluid with a constant equation of state w. We show that density perturbations in perfect fluids exhibit negative instabilities during both the radiation and the matter domination, irrespective of the form of f(G). This growth of perturbations gets stronger on smaller scales, which is difficult to be compatible with the observed galaxy spectrum unless the deviation from General Relativity is very small. Thus f(G) cosmological models are effectively ruled out from this Ultra-Violet instability, even though they can be compatible with the late-time cosmic acceleration and local gravity constraints.

Original languageEnglish
Pages (from-to)885-899
Number of pages15
JournalModern Physics Letters A
Volume25
Issue number11-12
DOIs
Publication statusPublished - 2010 Apr 20
Externally publishedYes

Keywords

  • Cosmological perturbations
  • Gauss-Bonnet
  • Modified gravity

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Astronomy and Astrophysics
  • Physics and Astronomy(all)

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