Journal ArticleDOI
Second-order scalar-tensor field equations in a four-dimensional space
TLDR
In this article, the second-order Euler-Lagrange tensors are derived from a Lagrangian which is at most of second order in the derivatives of the field functions.Abstract:
Lagrange scalar densities which are concomitants of a pseudo-Riemannian metric-tensor, a scalar field and their derivatives of arbitrary order are considered. The most general second-order Euler-Lagrange tensors derivable from such a Lagrangian in a four-dimensional space are constructed, and it is shown that these Euler-Lagrange tensors may be obtained from a Lagrangian which is at most of second order in the derivatives of the field functions.read more
Citations
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Inflation and primordial non-Gaussianities of "generalized Galileons"
TL;DR: In this article, Deffayet and Horndeski studied the cosmological implications of the generalized Galileon, which is the most general scalar field theory whose Lagrangian contains derivatives up to second order while keeping second order equations of motion.
Journal ArticleDOI
Viable cosmological solutions in massive bimetric gravity
TL;DR: In this article, the conditions for a viable cosmological solution at the background level in big gravity models were found and the conditions of a phantom behavior for a cosmology that cannot cross the phantom divide were identified.
Journal ArticleDOI
Inflation, Cosmic Perturbations and Non-Gaussianities
TL;DR: In this article, the theory of inflationary perturbations is reviewed at both linear and nonlinear orders and a variety of inflation models, emphasizing their signatures on cosmic perturbation are discussed.
Journal ArticleDOI
Spherical collapse in Galileon gravity: fifth force solutions, halo mass function and halo bias
TL;DR: In this article, the authors derived the nonlinear spherically symmetric equations in the quasi-static and weak-field limits, focusing on model parameters that fit current CMB, SNIa and BAO data.
Journal ArticleDOI
On the local well-posedness of Lovelock and Horndeski theories
Giuseppe Papallo,Harvey S. Reall +1 more
TL;DR: For Lovelock and Horndeski theories of gravity, this article showed that the equation of motion is always weakly hyperbolic for weak fields but, in a generic weak-field background, it is not strongly Hyperbolic.
References
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Journal ArticleDOI
Mach's principle and a relativistic theory of gravitation
Carl H. Brans,R. H. Dicke +1 more
TL;DR: In this paper, the role of Mach's principle in physics is discussed in relation to the equivalence principle and the difficulties encountered in attempting to incorporate Mach's principles into general relativity are discussed.
Journal ArticleDOI
The Einstein Tensor and Its Generalizations
TL;DR: In this paper, the number of independent tensors of this type depends crucially on the dimension of the space, and, in the four dimensional case, the only tensors with these properties are the metric and the Einstein tensors.
Journal ArticleDOI
Comments on the scalar-tensor theory
TL;DR: In this article, the ponderomotive laws of a scalar-tensor theory are constructed free of approximations in the form of integral laws, and the integrals are extended over two-and three-dimensional domains that lie entirely in empty space but surround the regions containing matter.
Journal ArticleDOI
The uniqueness of the einstein field equations in a four-dimensional space.
TL;DR: In this article, the Euler-Lagrange equations corresponding to a Lagrange density which is a function of g ≥ 2 and its first two derivatives are investigated and necessary and sufficient conditions for these equations to be of second order are obtained and it is shown that in a four-dimensional space the Einstein field equations (with cosmological term) are the only permissible second order Euler Lagrange equations.
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