Computing model independent perturbations in dark energy and modified gravity

Battye, Richard A.; Pearson, Jonathan A.

Abstract

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.

Citation

Battye, R. A., & Pearson, J. A. (2014). Computing model independent perturbations in dark energy and modified gravity. Journal of Cosmology and Astroparticle Physics, 2014(03), Article 051. https://doi.org/10.1088/1475-7516/2014/03/051

• Journal Article Type: Article
• Publication Date: 2014-03
• Deposit Date: Feb 26, 2014
• Publicly Available Date: Jul 8, 2014
• Journal: Journal of Cosmology and Astroparticle Physics
• Electronic ISSN: 1475-7516
• Publisher: IOP Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 2014
• Issue: 03
• Article Number: 051
• DOI: https://doi.org/10.1088/1475-7516/2014/03/051
• Keywords: Modified gravity, Cosmological perturbation theory, dark energy theory, Cosmological parameters from CMBR.
• Public URL: https://durham-repository.worktribe.com/output/1468519