In the present paper, we briefly review recent studies of second order gravitational perturbations in braneworld models. After we mention the possibility of pathological behavior of gravity in higher order perturbations, second order perturbations are discussed in RandallSundrum braneworld models. Since mass spectrums of each braneworld model are different, we analyze them by different approach...

In the present paper, we briefly review recent studies of second-order gravitational perturbations in braneworld models. After we consider the possibility of pathological behavior of gravity at higher orders of perturbation, second-order perturbations are discussed in Randall-Sundrum braneworld models. Because the mass spectra in these braneworld models are different, we analyze them using diff...

We show that quantum mechanical supersymmetries are emerged in Kaluza– Klein spectrum of linearized gravity in several warped backgrounds as a consequence of higher-dimensional general coordinate invariance. These emergent supersymmetries play an essential role for the spectral structure of braneworld gravity. We show that for the case of braneworld models with two codimension-1 branes the spec...

Gravity in five-dimensional braneworld backgrounds may exhibit extra scalar degrees of freedom with problematic features, including kinetic ghosts and strong coupling behavior. Analysis of such effects is hampered by the standard heuristic approaches to braneworld gravity, which use the equations of motion as the starting point, supplemented by orbifold projections and junction conditions. Here...

In this paper the first exact interior solution to Einstein’s field equations for a static and non-uniform braneworld star with local and non-local bulk terms is presented. It is shown that the bulk Weyl scalar U(r) is always negative inside the stellar distribution, in consequence it reduces both the effective density and the effective pressure. It is found that the anisotropy generated by bul...

A brief review of the field of braneworld cosmology, from its inception with the large extra dimension scenario, to aspects of cosmology in warped extra dimensions, including the RS-I and RS-II models, braneworld inflation, the Goldberger-Wise mechanism, mirage cosmology, the radion-induced phase transition in RS-I, possible gravity wave signals, and the DGP model.

Gravity in five-dimensional braneworld backgrounds often exhibits problematic features, including kinetic ghosts, strong coupling, and the vDVZ discontinuity. These problems are an obstacle to producing and analyzing braneworld models with interesting and potentially observable modifications of 4d gravity. We examine these problems in a general AdS5/AdS4 setup with two branes and localized curv...

The braneworld model of Dvali–Gabadadze–Porrati (DGP) is a theory where gravity is modified at large distances by the arrested leakage of gravitons off our four-dimensional universe. Cosmology in this model has been shown to support both “conventional” and exotic explanations of the dark energy responsible for today’s cosmic acceleration. We present new results for the gravitational field of a ...