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Self-accelerating universe in Galileon cosmology

Silva, FP; Koyama, K; (2009) Self-accelerating universe in Galileon cosmology. Physical Review D - Particles, Fields, Gravitation and Cosmology , 80 (12) 10.1103/PhysRevD.80.121301. Green open access

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We present a cosmological model with a solution that self-accelerates at late times without signs of ghost instabilities on small scales. The model is a natural extension of the Brans-Dicke (BD) theory including a nonlinear derivative interaction, which appears in a theory with the Galilean shift symmetry. The existence of the self-accelerating universe requires a negative BD parameter but, thanks to the nonlinear term, small fluctuations around the solution are stable on small scales. General relativity is recovered at early times and on small scales by this nonlinear interaction via the Vainshtein mechanism. At late time, gravity is strongly modified and the background cosmology shows a phantomlike behavior and the growth rate of structure formation is enhanced. Thus this model leaves distinct signatures in cosmological observations and it can be distinguished from standard LCDM cosmology.

Type: Article
Title: Self-accelerating universe in Galileon cosmology
Open access status: An open access version is available from UCL Discovery
DOI: 10.1103/PhysRevD.80.121301
Publisher version: http://dx.doi.org/10.1103/PhysRevD.80.121301
Language: English
Additional information: © 2009 The American Physical Society
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL SLASH
UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS
URI: https://discovery.ucl.ac.uk/id/eprint/1345879
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