Some Adventures in the Search for a Modified Gravity Explanation for Cosmic Acceleration

Abstract

The discovery of cosmic acceleration has raised the intriguing possibility that we are witnessing the first breakdown of General Relativity on cosmological scales. In this article I will briefly review current attempts to construct a theoretically consistent and observationally viable modification of gravity that is capable of describing the accelerating universe. I will discuss f(R) models, and their obvious extensions, and the DGP model as an example of extra-dimensional implementations. I will then briefly describe the Galileon models and their very recent multifield and curved space extensions - a class of four-dimensional effective field theories encoding extra dimensional modifications to gravity. This article is dedicated to the career of my friend and former colleague, Joshua Goldberg, and is written to appear in his festschrift.

17 pages, to appear in a festschrift for Joshua Goldberg

References in corpus (13)

• Dynamics of dark energy
• Dark Energy and the Accelerating Universe
• From k-essence to generalised Galileons
• Covariant Galileon
• Generalized Galileons: All scalar models whose curved background extensions maintain second-order field equations and stress tensors
• Approaches to Understanding Cosmic Acceleration
• Multi-field galileons and higher co-dimension branes
• Symmetries for Galileons and DBI scalars on curved space
• Ghosts, Instabilities, and Superluminal Propagation in Modified Gravity Models
• Bi-galileon theory I: motivation and formulation
• Ghost conditions for Gauss-Bonnet cosmologies
• de Sitter Galileon
• Instabilities of Spherical Solutions with Multiple Galileons and SO(N) Symmetry

Cited by in corpus (5)

• Nonlocal Gravity and Structure in the Universe
• Cosmology with Hu-Sawicki gravity in Palatini Formalism
• Growth of perturbations in nonlocal gravity with non-$\Lambda$CDM background
• Eckart heat-flux applicability in $F(\Phi ,X)R$ theories and the existence of temperature gradients
• Energy conditions in consistent perfect fluid cosmology