Related papers: Bigravity from gradient expansion
We consider a generalisation of the DGP model, by adding a second brane with localised curvature, and allowing for a bulk cosmological constant and brane tensions. We study radion and graviton fluctuations in detail, enabling us to check…
We discuss whether or not bigravity theory can be embedded into the braneworld setup. As a candidate, we consider Dvali-Gabadadze-Porrati two-brane model with the Goldberger-Wise radion stabilization. We will show that we can construct a…
The behaviour of the distance between two branes (the `radion') in a braneworld model with a bulk scalar field is investigated. We show that the BPS conditions of supergravity ensure that the dynamics of the scalar field and the radion are…
In brane world scenarios with a bulk scalar field between two branes it is known that 4-dimensional Einstein gravity is restored at low energies on either brane. By using a gauge-invariant gravitational and scalar perturbation formalism we…
We consider brane world models with interbrane separation stabilized by the Goldberger-Wise scalar field. For arbitrary background, or vacuum configurations of the gravitational and scalar fields in such models, we construct the second…
A Randall-Sundrum-like braneworld scenario is constructed in a 5D extension of the Lorentz-violating massive gravity. The gauge hierarchy problem is solved in current model. The linear perturbations are calculated, and it is found that the…
We investigate cosmological evolutions of the bulk scalar field $\phi(t)$ and the radion $d(t)$ in five-dimensional dilatonic two branes model. The bulk potential for the scalar field is taken as the exponential function $V_{bulk} \propto…
We systematically explore the spectrum of gravitational perturbations in codimension-1 DGP braneworlds, and find a 4D ghost on the self-accelerating branch of solutions. The ghost appears for any value of the brane tension, although…
In this work we study two types of five-dimensional braneworld models given by sine-Gordon potentials. In both scenarios, the thick brane is generated by a real scalar field coupled to gravity. We focus our investigation on the localization…
In this thesis, we discuss the idea of multigravity, namely the possibility that a significant component of gravity that we feel at intermediate distances (1 mm < r < 10^26 cm) is due to massive but ultralight gravitons. We demonstrate how…
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…
We analyze the propagation of a scalar field in multidimensional theories which include kinetic corrections in the brane, as a prototype for gravitational interactions in a four dimensional brane located in a (nearly) flat extra dimensional…
We propose a simple higher-derivative braneworld gravity model which contains a stable accelerating branch, in the absence of cosmological constant or potential, that can be used to describe the late time cosmic acceleration. This model has…
We obtain the full 5D graviton propagator in the Randall-Sundrum model with the Gauss-Bonnet interaction. From the decomposition of the graviton propagator on the brane, we show that localization of gravity arises in the presence of the…
We consider brane-induced gravity model in more than one extra dimensions, regularized by assuming that the bulk gravity is soft in ultraviolet. We study linear theory about flat multi-dimensional space-time and flat brane. We first find…
Theories with infinite volume extra dimensions open exciting opportunities for particle physics. We argued recently that along with attractive features there are phenomenological difficulties in this class of models. In fact, there is no…
We study the regularization of theories of ``brane induced'' gravity in codimension $N>1$. The brane can be interpreted as a thin dielectric with a large dielectric constant, embedded in a higher dimensional space. The kinetic term for the…
The effective four-dimensional, linearised gravity of a brane world model with one extra dimension and a single brane is analysed. The model includes higher order curvature terms (such as the Gauss-Bonnet term) and a conformally coupled…
Four dimensional gravity in the low energy limit of a higher dimensional theory has been expected to be a (generalized) Brans-Dicke theory. A subtle point in brane world scenarios is that the system of four dimensional effective…
Coupling the galileons to a curved background has been a tradeoff between maintaining second order equations of motion, maintaining the galilean shift symmetries, and allowing the background metric to be dynamical. We propose a construction…