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 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...

Braneworld models of dark energy are examined in the light of observations of high redshift type Ia supernovae. Braneworld models admit several novel and even exotic possibilities which include: (i) The effective equation of state of dark energy can be more negative than in LCDM: w ≤ −1; (ii) A class of braneworld models can encounter a ‘quiescent’ future singularity at which the energy density...

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...

We derive the general equations of motion for a braneworld containing a (localized) domain wall. Euclideanization gives the geometry for braneworld false vacuum decay. We explicitly derive these instantons and compute the amplitude for false vacuum decay. We also show how to construct a toy ekpyrotic instanton. Finally, we comment on braneworlds with a compact spatial direction and the adS soli...

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.

Braneworld scenario especially of the Randall-Sundrum type 2) have recently attracted much attention. In particular, cosmological models in this scenario have been studied actively 3), 4). It has been shown that braneworld cosmology seems to be consistent with the 4-dimensional conventional cosmology at least on scales much lower than that corresponding to the brane tension, provided bulk Weyl ...

Properties of Braneworld models of dark energy are reviewed. Braneworld models admit the following interesting possibilities: (i) The effective equation of state can be w ≤ −1 as well as w ≥ −1. In the former case the expansion of the universe is well behaved at all times and the universe does not run into a future ‘Big Rip’ singularity which is usually encountered by Phantom models. (ii) For a...

In Gauss-Bonnet braneworld cosmology, the Friedmann equation of our four-dimensional universe on 3-brane is modified in a high energy regime (Gauss-Bonnet regime), while the standard expansion law is reproduced in low energies (standard regime). We investigate the Gauss-Bonnet braneworld cosmological effect on the thermal relic density of cold dark matter when the freeze-out of the dark matter ...