Parameterizing scalar-tensor theories for cosmological probes

Abstract

We study the evolution of density perturbations for a class of $f(R)$ models which closely mimic $\Lambda$CDM background cosmology. Using the quasi-static approximation, and the fact that these models are equivalent to scalar-tensor gravity, we write the modified Friedmann and cosmological perturbation equations in terms of the mass $M$ of the scalar field. Using the perturbation equations, we then derive an analytic expression for the growth parameter $\gamma$ in terms of $M$, and use our result to reconstruct the linear matter power spectrum. We find that the power spectrum at $z\sim 0$ is characterized by a tilt relative to its General Relativistic form, with increased power on small scales. We discuss how one has to modify the standard, constant $\gamma$ prescription in order to study structure formation for this class of models. Since $\gamma$ is now scale and time dependent, both the amplitude and transfer function associated with the linear matter power spectrum will be modified. We suggest a simple parameterization for the mass of the scalar field, which allows us to calculate the matter power spectrum for a broad class of $f(R)$ models.

References in corpus (31)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Dynamics of dark energy
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Models of f(R) Cosmic Acceleration that Evade Solar-System Tests
• Three Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Polarization Analysis
• Disappearing cosmological constant in f(R) gravity
• Modified f(R) gravity consistent with realistic cosmology: from matter dominated epoch to dark energy universe
• Extended Theories of Gravity and their Cosmological and Astrophysical Applications
• Class of viable modified $f(R)$ gravities describing inflation and the onset of accelerated expansion
• Conditions for the cosmological viability of f(R) dark energy models
• Are f(R) dark energy models cosmologically viable ?
• The Large Scale Structure of f(R) Gravity
• Observational signatures of f(R) dark energy models that satisfy cosmological and local gravity constraints
• A Parameterized Post-Friedmann Framework for Modified Gravity
• Measuring the dark side (with weak lensing)
• Searching for modified growth patterns with tomographic surveys
• Observational Tests of Modified Gravity
• Cluster Constraints on f(R) Gravity
• Constraints on scalar-tensor models of dark energy from observational and local gravity tests
• Cosmological Constraints on f(R) Acceleration Models
• Non-linear Evolution of Matter Power Spectrum in Modified Theory of Gravity
• Cosmological evolution in exponential gravity
• The dispersion of growth of matter perturbations in f(R) gravity
• Aspects of cosmological expansion in F(R) gravity models
• Can f(R) Modified Gravity Theories Mimic a LCDM Cosmology?
• Phantom boundary crossing and anomalous growth index of fluctuations in viable f(R) models of cosmic acceleration
• Confronting General Relativity with Further Cosmological Data
• New Parametrization for the Scale Dependent Growth Function in General Relativity
• Cosmological constraints on the Hu-Sawicki modified gravity scenario
• Matter power spectrum in f(R) gravity with massive neutrinos
• Parametrization for the Scale Dependent Growth in Modified Gravity

Cited by in corpus (17)

• Modified Gravity and Cosmology
• Modified Gravity Theories on a Nutshell: Inflation, Bounce and Late-time Evolution
• Cosmology and Fundamental Physics with the Euclid Satellite
• Cosmology and fundamental physics with the Euclid satellite
• New constraints on $f(R)$ gravity from clusters of galaxies
• Effective action approach to cosmological perturbations in dark energy and modified gravity
• Cluster Abundance in f(R) Gravity Models
• A comparison of structure formation in minimally and non-minimally coupled quintessence models
• Early massive clusters and the bouncing coupled dark energy
• Testing Einstein Gravity with Cosmic Growth and Expansion
• Structure formation in Multiple Dark Matter cosmologies with long-range scalar interactions
• Computing model independent perturbations in dark energy and modified gravity
• Modified Gravity: the CMB, Weak Lensing and General Parameterisations
• Model Independent Tests of Cosmic Gravity
• Parametrization for the Scale Dependent Growth in Modified Gravity
• Constraining Scale Dependent Growth with Redshift Surveys
• The Direction of Gravity