Cosmological evolution in DHOST theories
arXiv:1810.12070 · doi:10.1088/1475-7516/2019/01/030
Abstract
In the context of Degenerate Higher-Order Scalar-Tensor (DHOST) theories, we study cosmological solutions and their stability properties. In particular, we explicitly illustrate the crucial role of degeneracy by showing how the higher order homogeneous equations in the physical frame (where matter is minimally coupled) can be recast in a system of equations that do not involve higher order derivatives. We study the fixed points of the dynamics, finding the conditions for having a de Sitter attractor at late times. Then we consider the coupling to matter field (described for convenience by a k-essence Lagrangian) and find the conditions to avoid gradient and ghost instabilities at linear order in cosmological perturbations, extending previous work. Finally, we apply these results to a simple subclass of DHOST theories, showing that de Sitter attractor conditions, no ghost and no gradient instabilities conditions (both in the self-accelerating era and in the matter dominated era) can be compatible.
arXiv comment17 pages, 2 figures. V2: error corrected in the effective dark energy equation of state
References in corpus (39)
- Modified Gravity and Cosmology
- The galileon as a local modification of gravity
- Beyond the Cosmological Standard Model
- Generalized G-inflation: Inflation with the most general second-order field equations
- From k-essence to generalised Galileons
- Dark Energy after GW170817: dead ends and the road ahead
- Strong constraints on cosmological gravity from GW170817 and GRB 170817A
- Dark Energy after GW170817 and GRB170817A
- Implications of the Neutron Star Merger GW170817 for Cosmological Scalar-Tensor Theories
- Healthy theories beyond Horndeski
- Cosmological Tests of Modified Gravity
- Degenerate higher derivative theories beyond Horndeski: evading the Ostrogradski instability
- Transforming gravity: from derivative couplings to matter to second-order scalar-tensor theories beyond the Horndeski Lagrangian
- The Effective Field Theory of Dark Energy
- Exploring gravitational theories beyond Horndeski
- Degenerate higher order scalar-tensor theories beyond Horndeski up to cubic order
- Essential Building Blocks of Dark Energy
- Extended Scalar-Tensor Theories of Gravity
- Degenerate higher order scalar-tensor theories beyond Horndeski and disformal transformations
- Cosmology of a covariant Galileon field
- Scalar-tensor theories and modified gravity in the wake of GW170817
- Gravitational Rainbows: LIGO and Dark Energy at its Cutoff
- A unifying description of dark energy
- Hamiltonian analysis of higher derivative scalar-tensor theories
- Effective Description of Higher-Order Scalar-Tensor Theories
- Generalized Galileon cosmology
- Healthy degenerate theories with higher derivatives
- Gravitational Wave Decay into Dark Energy
- Observational constraints on Galileon cosmology
- Vainshtein mechanism after GW170817
- Horndeski: beyond, or not beyond?
- Vainshtein Screening in Scalar-Tensor Theories before and after GW170817: Constraints on Theories beyond Horndeski
- Ostrogradsky in Theories with Multiple Fields
- Self-accelerating universe in scalar-tensor theories after GW170817
- Counting the degrees of freedom of generalized Galileons
- Exorcising the Ostrogradsky ghost in coupled systems
- Higher Derivative Field Theories: Degeneracy Conditions and Classes
- Dark energy scenario consistent with GW170817 in theories beyond Horndeski gravity
- Behind Horndeski: Structurally Robust Higher Derivative EFTs
Cited by in corpus (28)
- Horndeski theory and beyond: a review
- Dark Energy and Modified Gravity in Degenerate Higher-Order Scalar-Tensor (DHOST) theories: a review
- Testing modified gravity at cosmological distances with LISA standard sirens
- BlackHawk v2.0: A public code for calculating the Hawking evaporation spectra of any black hole distribution
- Hairy Schwarzschild-(A)dS black hole solutions in DHOST theories beyond shift symmetry
- Vainshtein regime in Scalar-Tensor gravity: constraints on DHOST theories
- Current and future constraints on cosmology and modified gravitational wave friction from binary black holes
- Reconsidering the Ostrogradsky theorem: Higher-derivatives Lagrangians, Ghosts and Degeneracy
- Degeneracy, matter coupling, and disformal transformations in scalar-tensor theories
- Stealth dark energy in scordatura DHOST theory
- Constraining DHOST theories with linear growth of matter density fluctuations
- Effective field theory of degenerate higher-order inflation
- CMB constraints on DHOST theories
- Superluminality in DHOST theory with extra scalar
- Cosmological evolution of viable models in the generalized scalar-tensor theory
- Spatially covariant gravity with a dynamic lapse function
- Late time cosmological evolution in DHOST models
- Gravitational couplings in Chameleon models
- Cosmological Instabilities and the Role of Matter Interactions in Dynamical Dark Energy Models
- Non-Gaussianity in DHOST inflation
- Beyond Horndeski interactions induced by quantum effects
- Recent Developments in Degenerate Higher Order Scalar Tensor Theories
- CMB bispectrum constraints on DHOST inflation
- Primordial gravitational waves in DHOST inflation
- On phenomenological parametrizations for the luminosity distance of gravitational waves
- Cosmic evolution in DHOST theories with scaling solutions
- Scale-dependence in DHOST inflation
- Scalar-scalar-tensor interaction in DHOST theories