Standard cosmology from sigma-model

Abstract

We investigate (4+1)-and (5+0)-dimensional gravity coupled to a non-compact scalar field sigma-model and a perfect fluid within the context of the Randall-Sundrum scenario. We find cosmological solutions with a rolling fifth radius and a family of warp factors. Included in this family are both the original Randall-Sundrum solution and the self-tuning solution of Kachru, Schulz and Silverstein. Our solutions exhibit conventional cosmology.

Adding matter to Poincaré invariant branes

“…[15]. However, there has been little, and only very recent, work on the cosmology of automatically Poincare invariant branes [16].…”

Cosmological solutions of supergravity in singular spaces

“…In order to explore the transition between an accelerating universe and matter domination we need to consider the bulk solution in a perfect fluid. For example, [11] has considered a self-tuned domain wall in five dimensional gravity coupled to a scalar field with bulk fluid, obtaining matter dominated FRW dynamics induced on the brane. Coupling this to our mechanism for an accelerating universe should result in a rich cosmology, such as a modified Friedmann equation on the brane-world.…”

“…Notice that these conditions are automatically satisfied due to the assignment (11). The equations of motion can be written in BPS form…”

Bouncing branes

“…We make the ansatz that both the potentials U and V are of Liouville type: (6) and that the metric is:…”

“…The wormhole is time-dependent and the bounce involves the entire Universe. Our analysis will be along the lines of the one in [6].…”