Modified Friedmann equations in R-1-modified gravity

Xin He Meng, Peng Wang

Research output: Contribution to journalReview articlepeer-review

132 Scopus citations


Recently, corrections to the Einstein-Hilbert action that become important at small curvature have been proposed. We discuss the first-order and second-order approximations to the field equations derived by the Palatini variational principle. We work out the first-and second-order modified Friedmann equations and present the upper redshift bounds when these approximations are valid. We show that the second-order effects can be neglected in the cosmological predictions involving only the Hubble parameter, e.g. the various cosmological distances, but the second-order effects cannot be neglected in the predictions involving the derivatives of the Hubble parameter. Furthermore, the modified Friedmann equations fit the SNe Ia data at an acceptable level.

Original languageEnglish
Pages (from-to)4949-4961
Number of pages13
JournalClassical and Quantum Gravity
Issue number22
StatePublished - 21 Nov 2003
Externally publishedYes


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