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Title: Effective field theory of dark energy: a dynamical analysis

The effective field theory (EFT) of dark energy relies on three functions of time to describe the dynamics of background cosmology. The viability of these functions is investigated here by means of a thorough dynamical analysis. While the system is underdetermined, and one can always find a set of functions reproducing any expansion history, we are able to determine general compatibility conditions for these functions by requiring a viable background cosmology. In particular, we identify a set of variables that allows us to transform the non-autonomous system of equations into an infinite-dimensional one characterized by a significant recursive structure. We then analyze several autonomous sub-systems, obtained truncating the original one at increasingly higher dimension, that correspond to increasingly general models of dark energy and modified gravity. Furthermore, we exploit the recursive nature of the system to draw some general conclusions on the different cosmologies that can be recovered within the EFT formalism and the corresponding compatibility requirements for the EFT functions. The machinery that we set up serves different purposes. It offers a general scheme for performing dynamical analysis of dark energy and modified gravity models within the model independent framework of EFT; the general results, obtained with this technique,more » can be projected into specific models, as we show in one example. It also can be used to determine appropriate ans├Ątze for the three EFT background functions when studying the dynamics of cosmological perturbations in the context of large scale structure tests of gravity.« less
Authors:
; ;  [1]
  1. SISSA - International School for Advanced Studies, Via Bonomea 265, 34136, Trieste (Italy)
Publication Date:
OSTI Identifier:
22369758
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 02; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AUGMENTATION; COSMOLOGY; EQUATIONS; EXPANSION; FIELD THEORIES; FUNCTIONS; GRAVITATION; NONLUMINOUS MATTER; PERTURBATION THEORY; TIME DEPENDENCE