Minimal parameterizations for modified gravity
arXiv:1303.3197 · doi:10.1103/PhysRevD.88.083513
Abstract
The increasing precision of cosmological data provides us with an opportunity to test general relativity (GR) on the largest accessible scales. Parameterizing modified gravity models facilitates the systematic testing of the predictions of GR, and gives a framework for detecting possible deviations from it. Several different parameterizations have already been suggested, some linked to classifications of theories, and others more empirically motivated. Here we describe a particular new approach which casts modifications to gravity through two free functions of time and scale, which are directly linked to the field equations, but also easy to confront with observational data. We compare our approach with other existing methods of parameterizing modied gravity, specifically the parameterized post-Friedmann approach and the older method using the parameter set . We explain the connection between our parameters and the physics that is most important for generating cosmic microwave background anisotropies. Some qualitative features of this new parameterization, and therefore modifications to the gravitational equations of motion, are illustrated in a toy model, where the two functions are simply assumed to be constant parameters.
8 pages, 7 figures, 1 table
References in corpus (11)
- Quantum Gravity at a Lifshitz Point
- Modified f(R) gravity consistent with realistic cosmology: from matter dominated epoch to dark energy universe
- Dark matter and cosmic structure
- The WiggleZ Dark Energy Survey: Final data release and cosmological results
- Testing gravity with CAMB and CosmoMC
- The Parameterized Post-Friedmann Framework for Theories of Modified Gravity: Concepts, Formalism and Examples
- How to optimally parametrize deviations from General Relativity in the evolution of cosmological perturbations
- A practical approach to cosmological perturbations in modified gravity
- CMB temperature lensing power reconstruction
- The parameter space in Galileon gravity models
- Incompatibility of Rotation Curves with Gravitational Lensing for TeVeS