In this contribution, I review the basic ingredients of the so-called braneworld models. These models are based on the assumption that our universe is a brane: a sub-space embedded in a higher dimensional bulk spacetime. In contrast with the traditional Kaluza-Klein treatment of extra dimensions, ordinary matter fields are confined on the brane. As a consequence, the size of the extra-dimension...

Cosmic microwave background (CMB) observations provide in principle a high-precision test of models which are motivated by M theory. We set out the framework of a program to compute the tensor anisotropies in the CMB that are generated in braneworld models. In the simplest approximation, we show the braneworld imprint as a correction to the power spectra for standard temperature and polarizatio...

Lovelock gravity is an important extension of General Relativity that provides a promising framework to study curvature corrections to the Ein-stein action, while avoiding ghosts and keeping second order field equations. This paper derives the greybody factors for D-dimensional black holes arising in a theory with a Gauss-Bonnet curvature-squared term. These factors describe the non-trivial cou...

We explore the signatures of quintessence and modified gravity theories in the relativistic description of galaxy clustering within a parametrized post-Friedmann framework. For this purpose, we develop a calibration method to consistently account for horizon-scale effects in the linear parametrized post-Friedmann perturbations of minimally and nonminimally coupled scalar-tensor theories and tes...

Abstract. We place observational likelihood constraints on braneworld and non-commutative inflation for a number of inflaton potentials, using Planck, WMAP polarization and BAO data. Both braneworld and non-commutative scenarios of the kind considered here are limited by the most recent data even more severely than standard general-relativity models. At more than 95% confidence level, the monom...

In the context of an inflationary Randall-Sundrum Type II braneworld (RS2) we calculate spectral indices and amplitudes of cosmological scalar and tensor perturbations, up to second order in slow-roll parameters. Under very simple assumptions, extrapolating next-order formulas from first-order calculations in the case of a de Sitter brane, we see that the degeneracy between standard and branewo...

We obtain new results for consistent braneworld Kaluza-Klein reductions, showing how we can derive four-dimensional N = 2 gauged supergravity " localised on the AdS 4 brane " as an exact embedding in five-dimensional N = 4 gauged supergravity. Similarly, we obtain five-dimensional N = 2 gauged supergravity localised on an AdS 5 brane as a consistent Kaluza-Klein reduction from six-dimensional N...

In the context of $f(T,B)$ modified teleparallel gravity, we investigate influence torsion scalar $T$ and boundary term $B$ on confinement both gauge vector Kalb-Ramond fields. Both fields require a suitable coupling in five-dimensional braneworld scenarios to yield normalizable zero mode. We propose Stueckelberg-like geometrical that non-minimally couples term. To set up our models, use first-...

Gravity is so different from other fundamental forces that it now essentially treated as a nonfundamental force of entropic origin. Several good studies have been carried out in this direction. Quantum gravity theory which combines well with quantum physics. However, there are still many impediments to our understanding, especially the limits extreme. The effects start appearing on scene at Pla...