Conformal quantum effects and the anisotropic singularities of scalar-tensor theories of gravity
نویسندگان
چکیده
We show that the inclusion of a term CabcdC abcd in the action can remove the recently described anisotropic singularity occurring on the hypersurface F (φ) = 0 of scalar-tensor theories of gravity of the type
منابع مشابه
Conformal mappings preserving the Einstein tensor of Weyl manifolds
In this paper, we obtain a necessary and sufficient condition for a conformal mapping between two Weyl manifolds to preserve Einstein tensor. Then we prove that some basic curvature tensors of $W_n$ are preserved by such a conformal mapping if and only if the covector field of the mapping is locally a gradient. Also, we obtained the relation between the scalar curvatures of the Weyl manifolds r...
متن کاملSingularities in scalar - tensor gravity
The analysis of certain singularities in scalar-tensor gravity contained in a recent paper is completed, and situations are pointed out in which these singularities cannot occur. Recently, Abramo et al. [1] have investigated certain geometric singularities occurring in the gravitational sector of scalar-tensor theories described by the action
متن کاملScalar vacuum structure in general relativity and alternative theories . Conformal continuations
We discuss the global properties of static, spherically symmetric configurations of a self-gravitating real scalar field φ in general relativity (GR), scalar-tensor and high-order (curvature-nonlinear) theories of gravity in various dimensions. In GR, for scalar fields with an arbitrary potential V (φ) , not necessarily positive-definite, it is shown that the list of all possible types of space...
متن کاملOn Newtonian singularities in higher derivative gravity models
We consider the problem of Newtonian singularity in the wide class of higher derivative gravity models, including the ones which are renormalizable and superrenormalizable at the quantum level. The simplest version of the singularity-free theory has four derivatives and is pretty well-known. We argue that in all cases of local higherderivative theories, when the poles of the propagator are real...
متن کاملتبدیلات دوگانگی آبلی استاندارد در گرانش f(T)
According to the perturbation order, the equations of motion of low-energy string effective action are the generalized Einstein equations. Thus, by making use of the conformal transformation of the metric tensor, it is possible to map the low-energy string effective action into f(T) gravity, relating the dilaton field to the torsion scalar. Considering a homogeneous and isotropic universe and ...
متن کامل