Effective field theory approach to modified gravity including Horndeski theory and Hořava-Lifshitz gravity

Ryotaro Kase, Shinji Tsujikawa

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

In this paper, we review the effective field theory of modified gravity in which the Lagrangian involves three-dimensional geometric quantities appearing in the 3+1 decomposition of spacetime. On the flat isotropic cosmological background, we expand a general action up to second-order in the perturbations of geometric scalars, by taking into account spatial derivatives higher than two. Our analysis covers a wide range of gravitational theories - including Horndeski theory/its recent generalizations and the projectable/nonprojectable versions of Hořava-Lifshitz gravity. We derive the equations of motion for linear cosmological perturbations and apply them to the calculations of inflationary power spectra as well as the dark energy dynamics in Galileon theories. We also show that our general results conveniently recover stability conditions of Hořava-Lifshitz gravity already derived in the literature.

Original languageEnglish
Article number1443008
JournalInternational Journal of Modern Physics D
Volume23
Issue number13
DOIs
Publication statusPublished - 2014 Nov 16
Externally publishedYes

Keywords

  • Cosmology
  • dark energy
  • modified gravity
  • quantum gravity

ASJC Scopus subject areas

  • Mathematical Physics
  • Astronomy and Astrophysics
  • Space and Planetary Science

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