Degrees of freedom of f(T) gravity

Li, Miao; Miao, Ran; Miao, Yan-Gang

doi:10.1007/jhep07(2011)108

Cited by 201 publications

(168 citation statements)

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“…[8]), the f (T ) field equations are second order in the field derivatives since the torsion scalar is a function of the square of the first derivatives of the tetrads field. Furthermore, as for f (R) theories, the generalized TEGR displays additional degrees of freedom (whose physical nature is still under investigation [14]) related to the fact that the equations of motion are not invariant under local Lorentz transformations [15]. In particular, this implies the existence of a preferential global reference frame defined by the autoparallel curves of the manifold that solve the equations of motion.…”

Section: Introductionmentioning

confidence: 99%

Weak-field spherically symmetric solutions inf(T)gravity

2015

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We study weak-field solutions having spherical symmetry in f (T ) gravity; to this end, we solve the field equations for a non diagonal tetrad, starting from Lagrangian in the form f (T ) = T +αT n , where α is a small constant, parameterizing the departure of the theory from GR. We show that the classical spherically symmetric solutions of GR, i.e. the Schwarzschild and Schwarzschild-de Sitter solutions, are perturbed by terms in the form ∝ r 2−2n and discuss the impact of these perturbations in observational tests. * Electronic address: matteo.ruggiero@polito.it † Electronic address: ninfa.radicella@sa.infn.it

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Section: Introductionmentioning

confidence: 99%

Weak-field spherically symmetric solutions inf(T)gravity

2015

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“…A key problem in f (T ) gravity is that it breaks the invariance under local Lorentz transformations complicating the interpretation of the relationship between all inertial frames of the tangent space to the differentiable manifold (space-time) [63,64]. This problem may lead to the emergence of spurious new degrees of freedom, which are responsible for the breakdown of the local Lorentz symmetry [65]. A consequence of the formulation of the theory using a scalar which is not invariant under local Lorentz transformations, the torsion scalar T in this case, is that instead of the theory presenting differential equations of motion of fourth order, as in the case of f (R) gravity, it has second-order differential equations.…”

Section: Introductionmentioning

confidence: 99%

Generalized teleparallel theory

Ednaldo

Rodrigues

2016

Eur. Phys. J. C

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We construct a theory in which the gravitational interaction is described only by torsion, but that generalizes the teleparallel theory still keeping the invariance of local Lorentz transformations in one particular case. We show that our theory falls, in a certain limit of a real parameter, under f (R) gravity or, in another limit of the same real parameter, under modified f (T ) gravity; on interpolating between these two theories it still can fall under several other theories. We explicitly show the equivalence with f (R) gravity for the cases of a Friedmann-Lemaître-Robertson-Walker flat metric for diagonal tetrads, and a metric with spherical symmetry for diagonal and non-diagonal tetrads. We study four applications, one in the reconstruction of the de Sitter universe cosmological model, for obtaining a static spherically symmetric solution of de Sitter type for a perfect fluid, for evolution of the state parameter ω DE , and for the thermodynamics of the apparent horizon.

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“…The f (T ) theory of gravity is non local Lorentz invariant theory. To resolve this problem, a lot of work has been done in this direction (Li, Sotiriou & Barrow 2011;Li, Miao & Miao 2011). Nashed (2015) proposed general tetrad field by regularization of f (T ) field equations which has two tetrad matrices.…”

Section: Introductionmentioning

confidence: 99%

Dynamical instability of cylindrical symmetric collapsing star in generalized teleparallel gravity

Jawad

Momeni

Rani

et al. 2016

Astrophys Space Sci

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This paper is devoted to analyze the dynamical instability of a self-gravitating object undergoes to collapse process. We take the framework of generalized teleparallel gravity with cylindrical symmetric gravitating object. The matter distribution is represented by locally anisotropic energy-momentum tensor. We develop basic equations such as dynamical equations along with matching conditions and Harrison-Wheeler equation of state. By applying linear perturbation strategy, we construct collapse equation which is used to accomplish the instability ranges in Newtonian and post-Newtonian regimes. We find these ranges for isotropic pressure as well as reduce the results in general relativity. The unstable behavior depends on matter, metric, mass and torsion based terms. *

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Degrees of freedom of f(T) gravity

Cited by 201 publications

References 14 publications

Weak-field spherically symmetric solutions inf(T)gravity

Weak-field spherically symmetric solutions inf(T)gravity

Generalized teleparallel theory

Dynamical instability of cylindrical symmetric collapsing star in generalized teleparallel gravity

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