Generalized Galileon cosmology

By Antonio de Felice, S. Tsujikawa. 2010

154 citations recorded by the source corpus.

We study the cosmology of a generalized Galileon field $\ensuremath{\phi}$ with five covariant Lagrangians in which $\ensuremath{\phi}$ is replaced by general scalar functions ${f}_{i}(\ensuremath{\phi})$ ($i=1,\dots{},5$). For these theories, the equations of motion remain at second order in time derivatives. We constrain the forms of the functions ${f}_{i}(\ensuremath{\phi})$ from the requirement to possess de Sitter solutions responsible for dark energy. There are two possible choices for power-law functions ${f}_{i}(\ensuremath{\phi})$, depending on whether the coupling $F(\ensuremath{\phi})$ with the Ricci scalar $R$ is independent of $\ensuremath{\phi}$ or depends on $\ensuremath{\phi}$. The former corresponds to the covariant Galileon theory that respects the Galilean symmetry in the Minkowski space-time. For generalized Galileon theories we derive the conditions for the avoidance of ghosts and Laplacian instabilities associated with scalar and tensor perturbations as well as the condition for the stability of de Sitter solutions. We also carry out a detailed analytic and numerical study for the cosmological dynamics in those theories.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/5ff5c06959939f24899e638067090884585f325a

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Citations in the corpus

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].”
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]).”
Cosmology in generalized Proca theories (2016, result): “While even p-form Galileons and multi odd p-form Galileons are easy to construct, very soon it was realized that one cannot construct Galilean interactions for a Lorentz- and gauge-invariant, single spin-1 (i.e., 1-form) field in any dimensions [26] (see also Refs.”
f(T) teleparallel gravity and cosmology (2015, methodology): “The simplest models are those with non-minimally coupled and non-minimalderivatively coupled scalar fields, or more generally the Horndeski [331] and generalized Galileon theories [618].”
Cosmological tests of modified gravity (2015, background): “[99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 97, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121] for an incomplete list of studies of cosmology in this class of models.”