Phenomenology of dark energy: exploring the space of theories with future redshift surveys

Abstract

We use the effective field theory of dark energy to explore the space of modified gravity models which are capable of driving the present cosmic acceleration. We identify five universal functions of cosmic time that are enough to describe a wide range of theories containing a single scalar degree of freedom in addition to the metric. The first function (the effective equation of state) uniquely controls the expansion history of the universe. The remaining four functions appear in the linear cosmological perturbation equations, but only three of them regulate the growth history of large scale structures. We propose a specific parameterization of such functions in terms of characteristic coefficients that serve as coordinates in the space of modified gravity theories and can be effectively constrained by the next generation of cosmological experiments. We address in full generality the problem of the soundness of the theory against ghost-like and gradient instabilities and show how the space of non-pathological models shrinks when a more negative equation of state parameter is considered. This analysis allows us to locate a large class of stable theories that violate the null energy condition (i.e. super-acceleration models) and to recover, as particular subsets, various models considered so far. Finally, under the assumption that the true underlying cosmological model is the $\Lambda$ Cold Dark Matter ($\Lambda$CDM) scenario, and relying on the figure of merit of EUCLID-like observations, we demonstrate that the theoretical requirement of stability significantly narrows the empirical likelihood, increasing the discriminatory power of data. We also find that the vast majority of these non-pathological theories generating the same expansion history as the $\Lambda$CDM model predict a different, lower, growth rate of cosmic structures.

v1: 28 pages, 20 pdf figures. v2: 29 pages, minor improvements in the text, figures improved

References in corpus (22)

• Dynamics of dark energy
• Cosmology and the Fate of Dilatation Symmetry
• Resummation of Massive Gravity
• Spectra and Light Curves of Six Type Ia Supernovae at 0.511 < z < 1.12 and the Union2 Compilation
• The Effective Field Theory of Inflation
• Covariant Galileon
• Causality, Analyticity and an IR Obstruction to UV Completion
• Generalized Galileons: All scalar models whose curved background extensions maintain second-order field equations and stress tensors
• Conditions for the cosmological viability of f(R) dark energy models
• A test of the nature of cosmic acceleration using galaxy redshift distortions
• Imperfect Dark Energy from Kinetic Gravity Braiding
• Starting the Universe: Stable Violation of the Null Energy Condition and Non-standard Cosmologies
• A Parameterized Post-Friedmann Framework for Modified Gravity
• Galileon Cosmology
• Degravitation of the Cosmological Constant and Graviton Width
• The Effective Theory of Quintessence: the w<-1 Side Unveiled
• Coupled and Extended Quintessence: theoretical differences and structure formation
• The Parameterized Post-Friedmann Framework for Theories of Modified Gravity: Concepts, Formalism and Examples
• Model-independent constraints on the cosmological anisotropic stress
• Consistent perturbations in an imperfect fluid
• Observable physical modes of modified gravity
• Big Bang Nucleosynthesis Constraints on the Self-Gravity of Pressure

Cited by in corpus (57)

• Cosmological Tests of Modified Gravity
• Exploring gravitational theories beyond Horndeski
• Maximal freedom at minimum cost: linear large-scale structure in general modifications of gravity
• A unifying description of dark energy
• The VIMOS Public Extragalactic Redshift Survey (VIPERS): The growth of structures at $0.5<z<1.2$ from redshift-space distortions in the clustering of the PDR-2 final sample
• Effective Field Theory of Dark Energy: a Review
• Effective Field Theory of Cosmic Acceleration: constraining dark energy with CMB data
• Effective Description of Higher-Order Scalar-Tensor Theories
• Limits of Quasi-Static Approximation in Modified-Gravity Cosmologies
• The Observational Future of Cosmological Scalar-Tensor Theories
• Piercing the Vainshtein screen with anomalous gravitational wave speed: Constraints on modified gravity from binary pulsars
• Effective Theory of Interacting Dark Energy
• Evidence for suppression of structure growth in the concordance cosmological model
• Extending cosmological tests of General Relativity with the Square Kilometre Array
• Hamiltonian structure of scalar-tensor theories beyond Horndeski
• Effective Theory of Dark Energy at Redshift Survey Scales
• Is cosmic acceleration proven by local cosmological probes?
• Phenomenology of the generalized cubic covariant Galileon model and cosmological bounds
• A comparison of Einstein-Boltzmann solvers for testing General Relativity
• Phenomenology of dark energy: general features of large-scale perturbations
• Effective field theory approach to modified gravity including Horndeski theory and Hořava-Lifshitz gravity
• The effective field theory of inflation/dark energy and the Horndeski theory
• Cosmology in generalized Horndeski theories with second-order equations of motion
• An Extended action for the effective field theory of dark energy: a stability analysis and a complete guide to the mapping at the basis of EFTCAMB
• The road ahead of Horndeski: cosmology of surviving scalar-tensor theories
• Constraints on modified gravity from Planck 2015: when the health of your theory makes the difference
• Weakening Gravity on Redshift-Survey Scales with Kinetic Matter Mixing
• Optimising growth of structure constraints on modified gravity
• Reconstructing Horndeski theories from phenomenological modified gravity and dark energy models on cosmological scales
• Possibility of realizing weak gravity in redshift space distortion measurements
• Using dark energy to suppress power at small scales
• Model-independent cosmic acceleration and type Ia supernovae intrinsic luminosity redshift dependence
• An effective description of dark matter and dark energy in the mildly non-linear regime
• Observational signatures of the theories beyond Horndeski
• Reconstructing Horndeski models from the effective field theory of dark energy
• Spatially covariant theories of gravity: disformal transformation, cosmological perturbations and the Einstein frame
• The role of the tachyonic instability in Horndeski gravity
• Diagnostic of Horndeski Theories
• Cosmological constraints on Hořava gravity revised in light of GW170817 and GRB170817A and the degeneracy with massive neutrinos
• Comparison of different approaches to the quasi-static approximation in Horndeski models
• Non-local bias contribution to third-order galaxy correlations
• Cosmological tests of modified gravity: constraints on $F(R)$ theories from the galaxy clustering ratio
• Gravitational Redshift Constraints on the Effective Theory of Interacting Dark Energy
• K-mouflage Imprints on Cosmological Observables and Data Constraints
• An Accurate Fitting Function For Scale-dependent Growth Rate in Hu-Sawicki $f(R)$ Gravity
• The trace of the trace of the energy-momentum tensor-dependent Einstein's field equations
• Inflationary gravitational waves in the effective field theory of modified gravity
• Cosmological disformal transformations to the Einstein frame and gravitational couplings with matter perturbations
• The effective field theory of K-mouflage
• Constraining extended cosmologies with GW$\times$LSS cross-correlations
• Cosmological Instabilities and the Role of Matter Interactions in Dynamical Dark Energy Models
• Extreme Mass Ratio Inspirals with Scalar Hair
• The effective field theory of dark energy diagnostic of linear Horndeski theories after GW170817 and GRB170817A
• Improvements in cosmological constraints from breaking growth degeneracy
• KiDS-Legacy: Constraints on Horndeski gravity from weak lensing combined with galaxy clustering and cosmic microwave background anisotropies
• Correlation of structure growth index with current cosmic acceleration: constraints on dark energy models
• Matter growth in extended $\Lambda$CDM cosmology