Family of scalar-nonmetricity theories of gravity

Rünkla, Mihkel; Vilson, Ott

doi:10.1103/physrevd.98.084034

Cited by 65 publications

(48 citation statements)

References 60 publications

(177 reference statements)

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“…In particular, one may consider more general theories, for example derived from a general constitutive relation [39], possibly including also parity-odd terms, or coupling to scalar fields [40][41][42][43], up to Horndeski-like teleparallel theories [44,45]. Further, taking inspiration from the socalled trinity of gravity [1], one may consider extensions to the symmetric teleparallel equivalent of gravity [46], and apply the parameterized post-Newtonian formalism to generalized theories based on the symmetric teleparallel geometry [47][48][49][50][51]. Another possible extension would be studying the motion of compact objects at higher orders in the post-Newtonian expansion, in order to derive the emitted gravitational waves [52].…”

Section: Discussionmentioning

confidence: 99%

Parametrized post-Newtonian limit of general teleparallel gravity theories

Ualikhanova

Hohmann

2019

Phys. Rev. D

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We derive the post-Newtonian limit of a general class of teleparallel gravity theories, whose action is given by a free function of three scalar quantities obtained from the torsion of the teleparallel connection. This class of theories is chosen to be sufficiently generic in order to include the f (T ) class of theories as well as new general relativity as subclasses. To derive its post-Newtonian limit, we first impose the Weitzenböck gauge, and then introduce a post-Newtonian approximation of the tetrad field around a Minkowski background solution. Our results show that the class of theories we consider is fully conservative, with only the parameters β and γ potentially deviating from their general relativity values. In particular, we find that the post-Newtonian limit of any f (T ) theory is identical to that of general relativity, so that these theories cannot be distinguished by measurements of the post-Newtonian parameters alone.

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Section: Discussionmentioning

confidence: 99%

Parametrized post-Newtonian limit of general teleparallel gravity theories

Ualikhanova

Hohmann

2019

Phys. Rev. D

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“…By construction, the nonmetricity scalar, Q, is equivalent to the Ricci scalar up to a boundary term in the Lagrangian [34]. This takes the form of…”

Section: Introductionmentioning

confidence: 99%

“…However, not much work has been done on other scalar invariant generalizations such as Gauss-Bonnet extensions. The possibility of a scalar field coupled to STG has been explored in a number of recent works [34,41] where the nonminimal coupling case was investigated. This is an interesting possibility for the extended f (Q, B) context due to the separation between second and fourth order contributions.…”

Section: Introductionmentioning

confidence: 99%

Polarization of gravitational waves in symmetric teleparallel theories of gravity and their modifications

et al. 2019

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Symmetric teleparallel gravity (STG) offers an interesting avenue to formulate a theory of gravitation that relies neither on curvature nor torsion but only on non-metricity Q. Given the growing number of confirmed observations of gravitational waves (GWs) and their use to explore gravitational theories, in this work we investigate the GWs in various extensions of STG, focusing on their speed and polarization. We explore the plethora of theories that this new framework opens up, that is, as general relativity (GR) can be modified, so to can the symmetric teleparallel equivalent of general relativity (STEGR). In this work, we investigate the fate of GWs in the generalized irreducible decomposition of STEGR, generalizations of the STEGR Lagrangian, f (Q), a scalar field nonminimally coupled to the STEGR Lagrangian, and the general setup of f (Q, B) theory where B is the boundary term difference between the Ricci scalar and the STEGR Lagrangian. Coincidentally, f (Q, B) forms a more general theory than f (R) gravity since Q embodies the second order elements of the Ricci scalar while B takes on it's fourth order boundary terms. Our work deals mainly with the resulting scalar-vector-tensor polarization modes of the plethora of STG theories, and how they effect their respective speeds of propagation.

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“…Scalar-tensor models form one of the largest and most well-studied classes of gravity theories. While this term most often refers to scalar-curvature theories [1], which can be regarded as scalar extensions of general relativity based on its standard formulation in terms of curvature, it can also appropriately be applied to scalar field extensions of teleparallel gravity based on torsion [2][3][4][5] or symmetric teleparallel gravity based on non-metricity [6,7], and hence to scalar extensions of each of the three geometric pictures of gravity [8].…”

Section: Introductionmentioning

confidence: 99%

Disformal Transformations in Scalar–Torsion Gravity

Hohmann

2019

Universe

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We study disformal transformations in the context of scalar extensions to teleparallel gravity, in which the gravitational interaction is mediated by the torsion of a flat, metric compatible connection. We find a generic class of scalar-torsion actions which is invariant under disformal transformations, and which possesses different invariant subclasses. For the most simple of these subclasses we explicitly derive all terms that may appear in the action. We propose to study actions from this class as possible teleparallel analogues of healthy beyond Horndeski theories.

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Family of scalar-nonmetricity theories of gravity

Cited by 65 publications

References 60 publications

Parametrized post-Newtonian limit of general teleparallel gravity theories

Parametrized post-Newtonian limit of general teleparallel gravity theories

Polarization of gravitational waves in symmetric teleparallel theories of gravity and their modifications

Disformal Transformations in Scalar–Torsion Gravity

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