Nonminimal couplings, gravitational waves, and torsion in Horndeski's theory
arXiv:1703.09686 · doi:10.1103/PhysRevD.96.084023
Abstract
The Horndeski Lagrangian brings together all possible interactions between gravity and a scalar field that yield second-order field equations in four-dimensional spacetime. As originally proposed, it only addresses phenomenology without torsion, which is a non-Riemannian feature of geometry. Since torsion can potentially affect interesting phenomena such as gravitational waves and early Universe inflation, in this paper we allow torsion to exist and propagate within the Horndeski framework. To achieve this goal, we cast the Horndeski Lagrangian in Cartan's first-order formalism, and introduce wave operators designed to act covariantly on p-form fields that carry Lorentz indices. We find that nonminimal couplings and second-order derivatives of the scalar field in the Lagrangian are indeed generic sources of torsion. Metric perturbations couple to the background torsion and new torsional modes appear. These may be detected via gravitational waves but not through Yang-Mills gauge bosons.
arXiv comment13 pages, no figures. v2: updated references. v3: Updated references, new subsection IV.C, accepted for publication in PRD
References in corpus (31)
- The galileon as a local modification of gravity
- Generalized G-inflation: Inflation with the most general second-order field equations
- Chern-Simons Modification of General Relativity
- Healthy theories beyond Horndeski
- Physical Aspects of the Space-Time Torsion
- Degenerate higher derivative theories beyond Horndeski: evading the Ostrogradski instability
- Emergent Gravity and the Dark Universe
- General second order scalar-tensor theory, self tuning, and the Fab Four
- Degenerate higher order scalar-tensor theories beyond Horndeski up to cubic order
- Cosmology with torsion: An alternative to cosmic inflation
- Speed of Gravitational Waves and the Fate of Scalar-Tensor Gravity
- Beyond Einstein-Cartan gravity: Quadratic torsion and curvature invariants with even and odd parity including all boundary terms
- Status of non-Riemannian cosmology
- How (Not) to Palatini
- Constraining some Horndeski gravity theories
- Topological gravity and transgression holography
- Towards the most general scalar-tensor theories of gravity: a unified approach in the language of differential forms
- Einstein-Cartan formulation of Chern-Simons Lorentz-violating Gravity
- Cosmology with Scalar-Euler form Coupling
- Universal Torsion-Induced Interaction from Large Extra Dimensions
- Torsion Constraints in the Randall--Sundrum Scenario
- Supersymmetric 3D model for gravity with gauge symmetry, mass generation and effective cosmological constant
- Fermion Masses Through Condensation in Spacetimes with Torsion
- Torsion as a Dark Matter Candidate from the Higgs Portal
- Weakly dynamic dark energy via metric-scalar couplings with torsion
- Torsion in Extra Dimensions and One-Loop Observables
- Topological gravity and Wess-Zumino-Witten term
- Updated limits on extra dimensions through torsion and LHC data
- Linearized gravity in terms of differential forms
- Generalized Chern-Simons Modified Gravity in First-Order Formalism
- Randall-Sundrum brane universe as a ground state for Chern-Simons gravity
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- Metric-affine Gravity and Inflation
- Horndeski theories confront the Gravity Probe B experiment
- Non-minimally coupled scalar field cosmology with torsion
- Non-zero torsion and late cosmology
- Acceleration in Friedmann cosmology with torsion
- Luminal Propagation of Gravitational Waves in Scalar-tensor Theories: The Case for Torsion
- Varying the Horndeski Lagrangian within the Palatini approach
- Cosmological inflation driven by a scalar torsion function
- Unimodular Einstein--Cartan gravity: Dynamics and conservation laws
- A metric-affine version of the Horndeski theory
- Is there any symmetry left in gravity theories with explicit Lorentz violation?
- Holographic renormalization of Horndeski gravity
- The cosmological principle in theories with torsion: The case of Einstein-Cartan-Dirac-Maxwell gravity
- Linear and Second-order Geometry Perturbations on Spacetimes with Torsion
- Cosmological Dark Matter Amplification through Dark Torsion
- A black hole solution in conformal supergravity
- Probing charge of compact objects with gravitational microlensing of gravitational waves
- Probing black hole `charge' from the binary black hole inspiral
- Asymptotically AdS black hole with a conformally-coupled scalar field in the first-order formalism of gravity
- (Quasi-)normal modes of rotating black holes and new solitons in Einstein-Gauss-Bonnet
- Cosserat elasticity as the weak-field limit of Einstein--Cartan relativity