Self-accelerating universe in Galileon cosmology

By Fabio P. Silva, K. Koyama. 2009

203 citations recorded by the source corpus.

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.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/259289479728bc523b74c9685536bcea8e41435a

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Citations in the corpus

Imperfect Dark Energy from Kinetic Gravity Braiding (2010, result): “See also Refs.”
Modified Gravity and Cosmology (2011, background): “The cosmological behaviour of a number of models that are inspired by the galileon have also been investigated (see, for example, [1145, 711, 704, 375, 714, 404]).”
A systematic approach to generalisations of General Relativity and their cosmological implications (2018, background): “The direct cosmological application of covariant Galileons witnessed a flurry of investigations concerning self-accelerating de Sitter solutions [223, 224], inflation [225, 226, 227, 228], dark energy and its observational implications [229, 222, 230, 231, 232, 51, 52].”
f(R) Theories (2010, background): “However, the same mechanism, at least in cosmology, seems to appear also in the FLRW background for scalar fields which do not possess such a symmetry (see [539, 351, 190]).”
Cosmology in generalized Proca theories (2016, background): “The application of covariant Galileons to cosmology witnessed a flurry of investigations concerning self-accelerating de Sitter solutions [31, 32], late-time cosmology and its observational implications [33–39], inflation [40–50], super-luminalities [51–54], and so on.”