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...

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 this work we investigate the $f(R,T)$ brane in scalar-tensor representation, where solutions of equations motions for source field engender topological defects with two-kink profiles. We use first-order formalism to obtain analytical and analyze how these modify structure auxiliary fields arising from representation theory. found that when model engenders solutions, are modified order allow ...

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 ...

ABSTRACT In this paper, we quantify the ability of multiple measurements high-redshift quasars to constrain several theories modified gravity, including Dvali–Gabadadze–Porrati braneworld scenario, generalized Chaplygin gas, f(T) and polytropic Cardassian model. Recently released sample 1598 with X-ray ultraviolet flux in redshift range 0.036 ? z 5.1003, as well a compilation 120 intermediate-l...

Braneworld effective action is constructed by two different methods based respectively on the Dirichlet and Neumann boundary value problems. The equivalence of these methods is shown due to nontrivial duality relations between special boundary operators of these two problems. Previously known braneworld action algorithms in two-brane Randall-Sundrum model are generalized to curved branes with d...

If the graviton possesses an arbitrarily small (but nonvanishing) mass, perturbation theory implies that cosmic strings have a nonzero Newtonian potential. Nevertheless in Einstein gravity, where the graviton is strictly massless, the Newtonian potential of a cosmic string vanishes. This discrepancy is an example of the van Dam–Veltman–Zakharov (VDVZ) discontinuity. We present a solution for th...

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...