Computing model independent perturbations in dark energy and modified gravity

We present a methodology for computing model independent perturbations in dark energy and modified gravity. This is done from the Lagrangian for perturbations, by showing how field content, symmetries, and physical principles are often sufficient ingredients for closing the set of perturbed fluid eq...

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Bibliographic Details
Published inarXiv.org
Main Authors Battye, Richard A, Pearson, Jonathan A
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 15.04.2014
Subjects
Computation
Dark energy
Equations of state
Gravitation
Mathematical models
Physics - Cosmology and Nongalactic Astrophysics
Physics - General Relativity and Quantum Cosmology
Physics - High Energy Physics - Theory
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Summary:We present a methodology for computing model independent perturbations in dark energy and modified gravity. This is done from the Lagrangian for perturbations, by showing how field content, symmetries, and physical principles are often sufficient ingredients for closing the set of perturbed fluid equations. The fluid equations close once "equations of state for perturbations" are identified: these are linear combinations of fluid and metric perturbations which construct gauge invariant entropy and anisotropic stress perturbations for broad classes of theories. Our main results are the proof of the equation of state for perturbations presented in a previous paper, and the development of the required calculational tools.
ISSN:2331-8422
DOI:10.48550/arxiv.1311.6737