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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Exploring Bouncing Cosmologies with Cosmological Surveys
TL;DR: In this article, the authors present two representative paradigms of very early universe physics: the new matter (or matter-ekpyrotic) bounce scenario and the matter-bounce inflation scenario.
Journal ArticleDOI
Screening the fifth force in the Horndeski's most general scalar-tensor theories
Ryotaro Kase,Shinji Tsujikawa +1 more
TL;DR: In this article, the Vainshtein mechanism was studied in the presence of a field coupling to the Ricci scalar, and conditions under which the mechanism is at work in a weak gravitational background.
Journal ArticleDOI
Is local H 0 at odds with dark energy EFT?
TL;DR: In this paper , the authors employ a generic two parameter family of evolving equations of state (EoS) for dark energy (DE) w DE(z) and mock BAO data, and demonstrate that if i) w de(z = 0) < -1 and ii) integrated DE density less than ΛCDM, then H 0 increases.
Journal ArticleDOI
Bounce beyond Horndeski with GR asymptotics and γ-crossing
TL;DR: In this paper, a spatially flat, stable bouncing universe solution whose asymptotic past and future are described by General Relativity (GR) with conventional massless scalar field is constructed.
Journal ArticleDOI
Noether analysis of Scalar-Tensor Cosmology
TL;DR: In this article, a scalar-tensor theory of gravity, containing an arbitrary coupling function and a general potential, is considered in the context of a spatially flat FLRW model, where a requirement of existence of the maximal possible number of autonomous integrals of motion is imposed.
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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