Extended mimetic gravity: Hamiltonian analysis and gradient instabilities

Abstract

We propose a novel class of degenerate higher-order scalar-tensor theories as an extension of mimetic gravity. By performing a noninvertible conformal transformation on "seed" scalar-tensor theories which may be nondegenerate, we can generate a large class of theories with at most three physical degrees of freedom. We identify a general seed theory for which this is possible. Cosmological perturbations in these extended mimetic theories are also studied. It is shown that either of tensor or scalar perturbations is plagued with gradient instabilities, except for a special case where the scalar perturbations are presumably strongly coupled, or otherwise there appear ghost instabilities.

14 pages; matches published version

Cited by in corpus (72)

• Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A${}^{\ast }$
• Horndeski theory and beyond: a review
• Dark Energy and Modified Gravity in Degenerate Higher-Order Scalar-Tensor (DHOST) theories: a review
• Cosmological dynamics of mimetic gravity
• Alive and well: mimetic gravity and a higher-order extension in light of GW170817
• Mimicking dark matter and dark energy in a mimetic model compatible with GW170817
• Mimetic gravity as DHOST theories
• Linear stability analysis of hairy black holes in quadratic degenerate higher-order scalar-tensor theories: Odd-parity perturbations
• On Rotating Black Holes in DHOST Theories
• General Relativity solutions with stealth scalar hair in quadratic higher-order scalar-tensor theories
• Charged rotating black holes coupled with nonlinear electrodynamics Maxwell field in the mimetic gravity
• Non-singular black holes and the Limiting Curvature Mechanism: A Hamiltonian perspective
• Higher Derivative Mimetic Gravity
• Existence and Instability of Novel Hairy Black Holes in Shift-symmetric Horndeski Theories
• Invertible disformal transformations with higher derivatives
• Event Horizon Telescope observations exclude compact objects in baseline mimetic gravity
• Black hole perturbations in DHOST theories: Master variables, gradient instability, and strong coupling
• Spatially covariant gravity with velocity of the lapse function: the Hamiltonian analysis
• Nonlinear definition of the shadowy mode in higher-order scalar-tensor theories
• Relativistic stars in degenerate higher-order scalar-tensor theories after GW170817
• Black hole perturbations in modified gravity
• Stability of magnetic black holes in general nonlinear electrodynamics
• Built-in scordatura in U-DHOST
• Cuscuton gravity as a classically stable limiting curvature theory
• Hamiltonian analysis of mimetic scalar gravity revisited
• New Weyl-invariant vector-tensor theory for the cosmological constant
• Generalized disformal Horndeski theories: cosmological perturbations and consistent matter coupling
• Extended Cuscuton as Dark Energy
• Quasinormal Modes from EFT of Black Hole Perturbations with Timelike Scalar Profile
• Gauge Field Mimetic Cosmology
• Dynamics of the generalized unimodular gravity theory
• Linear stability of black holes in shift-symmetric Horndeski theories with a time-independent scalar field
• Stealth dark energy in scordatura DHOST theory
• Invertible disformal transformations with arbitrary higher-order derivatives
• Linear stability of black holes with static scalar hair in full Horndeski theories: generic instabilities and surviving models
• Spatially covariant gravity: Perturbative analysis and field transformations
• Tidal Love Numbers from EFT of Black Hole Perturbations with Timelike Scalar Profile
• Effective description of generalized disformal theories
• Inflation with $0\le c_{\mathrm{s}}\le 1$
• Stability of Hairy Black Holes in Shift-Symmetric Scalar-Tensor Theories via the Effective Field Theory Approach
• Two-field mimetic gravity revisited and Hamiltonian analysis
• Consistency of higher derivative couplings to matter fields in scalar-tensor gravity
• Limiting curvature mimetic gravity for group field theory condensates
• Reconstruction of mimetic gravity in a non-singular bouncing universe from quantum gravity
• Disforming to Conformal Symmetry
• Consistency of matter coupling in modified gravity
• Approximately stealth black hole in higher-order scalar-tensor theories
• Gravity in mimetic scalar-tensor theories after GW170817
• Large-scale structure in mimetic Horndeski gravity
• Anisotropic Mimetic Cosmology
• Towards a viable effective field theory of mimetic gravity
• Spatially covariant gravity with a dynamic lapse function
• Ghost from constraints: a generalization of Ostrogradsky theorem
• Mimetic DBI Inflation in Confrontation with Planck2018 data
• Black hole perturbations in higher-order scalar-tensor theories: initial value problem and dynamical stability
• New Dynamical Degrees of Freedom from Invertible Transformations
• Generalisation of Conformal-Disformal Transformations of the Metric in Scalar-Tensor Theories
• Theories with limited extrinsic curvature and a nonsingular anisotropic universe
• Hamiltonian analysis of Mimetic gravity with higher derivatives
• Emergent scenario in mimetic gravity
• Tachyon Mimetic Inflation as an Instabilities-Free Model
• Mimetic-Metric-Torsion with induced Axial mode and Phantom barrier crossing
• Isotropic stellar model in mimetic theory
• Mimetic Curvaton
• Cosmological Dark sector from a Mimetic-Metric-Torsion perspective
• Ghost-free resummation of gravitational interactions of a 2-form gauge field
• Exact solution for rotating black holes in parity-violating gravity
• Extensions of two-field mimetic gravity
• Recent Developments in Degenerate Higher Order Scalar Tensor Theories
• Higher order mimetic gravity after GW170817
• Viable Intermediate Inflation in the Mimetic DBI Model
• Quasinormal Modes from EFT of Black Hole Perturbations in Vector-Tensor Gravity