Cosmological constraints on f(G) dark energy models

Zhou, Shuang-Yong; Copeland, Edmund J.; Saffin, Paul M.

Abstract

Modified gravity theories with the Gauss-Bonnet term G=R2?4R??R??+R????R???? have recently gained a lot of attention as a possible explanation of dark energy. We perform a thorough phase space analysis on the so-called f(G) models, where f(G) is some general function of the Gauss-Bonnet term, and derive conditions for the cosmological viability of f(G) dark energy models. Following the f(R) case, we show that these conditions can be nicely presented as geometrical constraints on the derivatives of f(G). We find that for general f(G) models there are two kinds of stable accelerated solutions, a de Sitter solution and a phantom-like solution. They co-exist with each other and which solution the universe evolves to depends on the initial conditions. Finally, several toy models of f(G) dark energy are explored. Cosmologically viable trajectories that mimic the ?CDM model in the radiation and matter dominated periods, but have distinctive signatures at late times, are obtained.

Citation

Zhou, S., Copeland, E. J., & Saffin, P. M. (2009). Cosmological constraints on f(G) dark energy models. Journal of Cosmology and Astroparticle Physics, 2009(7), https://doi.org/10.1088/1475-7516/2009/07/009

• Journal Article Type: Article
• Acceptance Date: Jun 19, 2009
• Publication Date: Jul 6, 2009
• Deposit Date: Apr 21, 2017
• Publicly Available Date: Apr 21, 2017
• Journal: Journal of Cosmology and Astroparticle Physics
• Electronic ISSN: 1475-7516
• Publisher: IOP Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 2009
• Issue: 7
• DOI: https://doi.org/10.1088/1475-7516/2009/07/009
• Public URL: https://nottingham-repository.worktribe.com/output/705519
• Publisher URL: http://iopscience.iop.org/article/10.1088/1475-7516/2009/07/009/meta