Anisotropic stress and stability in modified gravity models

Abstract

The existence of anisotropic stress of a purely geometrical origin seems to be a characteristic of higher order gravity models, and has been suggested as a probe to test these models observationally, for example in weak lensing experiments. In this paper, we seek to find a class of higher order gravity models of f(R,G) type that would give us a zero anisotropic stress and study the consequences for the viability of the actual model. For the special case of a de Sitter background, we identify a subclass of models with the desired property. We also find a direct link between anisotropic stress and the stability of the model as well as the presence of extra degrees of freedom, which seems to be a general feature of higher order gravity models. Particularly, setting the anisotropic stress equal to zero for a de Sitter background leads to a singularity that makes it impossible to reach the de Sitter evolution.

15 pages, v2: Minor changes in the text, typos corrected

References in corpus (49)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• Dynamics of dark energy
• The Cosmological Constant and Dark Energy
• f(R) Theories Of Gravity
• f(R) theories
• 4D Gravity on a Brane in 5D Minkowski Space
• Introduction to Modified Gravity and Gravitational Alternative for Dark Energy
• Is Cosmic Speed-Up Due to New Gravitational Physics?
• Dark Energy and the Accelerating Universe
• Modified Gauss-Bonnet theory as gravitational alternative for dark energy
• 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
• Gauss-Bonnet dark energy
• Conditions for the cosmological viability of f(R) dark energy models
• The Cosmology of Generalized Modified Gravity Models
• Curvature quintessence matched with observational data
• Avoiding Dark Energy with 1/R Modifications of 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)
• Dark energy cosmology from higher-order, string-inspired gravity and its reconstruction
• Construction of cosmologically viable f(G) gravity models
• The pattern of growth in viable f(R) cosmologies
• Probing Newton's Constant on Vast Scales: DGP Gravity, Cosmic Acceleration and Large Scale Structure
• Consistent modified gravity: dark energy, acceleration and the absence of cosmic doomsday
• Dark energy and dark matter as curvature effects
• The future evolution and finite-time singularities in $F(R)$-gravity unifying the inflation and cosmic acceleration
• Structure formation in the DGP cosmological model
• A Singularity Problem with f(R) Dark Energy
• Dark Energy versus Modified Gravity
• The stability of modified gravity models
• Current constraints on the cosmic growth history
• Testing General Relativity with Current Cosmological Data
• Ghosts, Instabilities, and Superluminal Propagation in Modified Gravity Models
• Solar system constraints on f(G) gravity models
• Generalized Gravity and a Ghost
• Probing modifications of General Relativity using current cosmological observations
• Cosmological Constraints on $f(G)$ Dark Energy Models
• Dark Energy: Mystery of the Millennium
• No-go theorem for k-essence dark energy
• Solar System Constraints on Gauss-Bonnet Mediated Dark Energy
• Ghost Constraints on Modified Gravity
• Curvature scalar instability in f(R) gravity
• Vacuum structure for scalar cosmological perturbations in Modified Gravity Models
• Matter instabilities in general Gauss-Bonnet gravity
• Theoretical Priors On Modified Growth Parametrisations
• Dark Energy in Practice

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• On the stability of the cosmological solutions in f(R,G) gravity
• Observables and unobservables in dark energy cosmologies
• The fate of large-scale structure in modified gravity after GW170817 and GRB170817A
• General Relativistic N-body simulations in the weak field limit
• The phenomenological approach to modeling the dark energy
• Unraveling the effective fluid approach for $f(R)$ models in the subhorizon approximation
• Effects of Anisotropic Stress in Interacting Dark Matter - Dark Energy Scenarios
• Cosmological Parameter Estimation with Large Scale Structure Observations
• Model-independent constraints on the cosmological anisotropic stress
• Consistent perturbations in an imperfect fluid
• Probing Dark Energy through Scale Dependence
• Machine learning constraints on deviations from general relativity from the large scale structure of the Universe
• On the current status of Modified Gravity
• Nonlinear cosmological consistency relations and effective matter stresses
• The traces of anisotropic dark energy in light of Planck
• Combined constraints on deviations of dark energy from an ideal fluid from Euclid and Planck
• Forecast constraints on Anisotropic Stress in Dark Energy using gravitational-waves
• The Effective Fluid approach for Modified Gravity and its applications
• Probing the Cosmological Principle with weak lensing shear
• Relativistic effects in the large-scale structure with effective dark energy fluids
• Tracking the validity of the quasi-static and sub-horizon approximations in modified gravity
• Lensing convergence and anisotropic dark energy in galaxy redshift surveys
• Sound Speed Resonance of Gravitational Waves in Gauss-Bonnet-coupled inflation
• Matter growth in extended $\Lambda$CDM cosmology