Distinguishing modified gravity from dark energy

By Edmund Bertschinger, Phillip Zukin. 2008

271 citations recorded by the source corpus.

The acceleration of the Universe can be explained either through dark energy or through the modification of gravity on large scales. In this paper we investigate modified gravity models and compare their observable predictions with dark energy models. Modifications of general relativity are expected to be scale independent on superhorizon scales and scale dependent on subhorizon scales. For scale-independent modifications, utilizing the conservation of the curvature scalar and a parametrized post-Newtonian formulation of cosmological perturbations, we derive results for large-scale structure growth, weak gravitational lensing, and cosmic microwave background anisotropy. For scale-dependent modifications, inspired by recent f(R) theories we introduce a parametrization for the gravitational coupling G and the post-Newtonian parameter {gamma}. These parametrizations provide a convenient formalism for testing general relativity. However, we find that if dark energy is generalized to include both entropy and shear stress perturbations, and the dynamics of dark energy is unknown a priori, then modified gravity cannot in general be distinguished from dark energy using cosmological linear perturbations.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/9c5f72a1f047e72972703239cd8a543044aa222a

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Nuclear and High Energy Physics

Citations in the corpus

THE ATACAMA COSMOLOGY TELESCOPE: COSMOLOGY FROM GALAXY CLUSTERS DETECTED VIA THE SUNYAEV–ZEL'DOVICH EFFECT (2010, background): “A deviation from this predicted growth rate, particularly on linear scales, would signal a breakdown of ΛCDM (see, e.g., Linder 2005; Bertschinger & Zukin 2008; Silvestri & Trodden 2009; Jain & Khoury 2010; Shapiro et al. 2010, and references therein).”
FIVE-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE OBSERVATIONS: COSMOLOGICAL INTERPRETATION (2008, unknown): “…al. 2007; Yamamoto et al. 2007; Chiba & Takahashi 2007; Bean et al. 2007; Hu & Sawicki 2007; Song et al. 2007; Daniel et al. 2008; Jain & Zhang 2007; Bertschinger & Zukin 2008; Amin et al. 2007; Hu 2008), as well as for determining the mass of neutrinos (Hu et al. 1998; Lesgourgues & Pastor 2006).”
Cosmology and Fundamental Physics with the Euclid Satellite (2012, methodology): “This parameterization has been widely employed (Bertschinger and Zukin 2008; Daniel and Linder 2010; Linder and Cahn 2007; Bean and Tangmatitham 2010; Pogosian et al. 2010; Zhao et al. 2010; Dossett et al. 2011; Hojjati et al. 2011, 2012).”
KiDS-450 + 2dFLenS: Cosmological parameter constraints from weak gravitational lensing tomography and overlapping redshift-space galaxy clustering (2017, background): “…equal in General Relativity (GR; in the absence of anisotropic stresses), their equality is generally broken in distinct modified gravity scenarios, in a way that can depend on both length-scale and time (e.g. Bertschinger & Zukin 2008; Baker, Ferreira & Skordis 2013; Pogosian & Silvestri 2016).”
Maximal freedom at minimum cost: linear large-scale structure in general modifications of gravity (2014, background): “Instead, one can assume that the dark-energy model preserves locality and is approximately quasi-static, which results in a particular behaviour of the perturbations with scale [10, 30–32].”
The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Constraining modified gravity (2016, unknown): “Here we consider general scalar-tensor theories using the BZ parametrisation (Bertschinger & Zukin 2008; Zhao et al. 2009), GM = 1 + β1λ 2 1k 2as 1 + λ21k 2as (11) γslip = 1 + β2λ 2 2k 2as 1 + λ22k 2as (12) with the gravitational slip, γslip, defined as γslip = φ ψ (13) and the dimensionless…”
f(R) Theories (2010, unknown): “13), we obtain [596, 547] (see also [84, 632, 631]) k(2) a2 Ψ ≃ − (2)δρm 2F (k(2)/a(2))(1− 2Q(2))F +M(2) (k2/a2)F +M2 , (10.”
Approaches to understanding cosmic acceleration (2009, unknown): “parametrizations have been introduced in [197, 212, 214, 215].”