English

Space-like Dp branes: accelerating cosmologies versus conformally de Sitter space-time

High Energy Physics - Theory 2015-06-23 v3

Abstract

We consider the space-like Dpp brane solutions of type II string theories having isometries ISO(p+1)(p+1) ×\times SO(8p,1)(8-p,1). These are asymptotically flat solutions or in other words, the metrics become flat at the time scale ττ0\tau \gg \tau_0. On the other hand, when ττ0\tau \sim \tau_0, we get (p+1)+1(p+1)+1 dimensional flat FLRWmetrics upon compactification on a (8p)(8-p) dimensional hyperbolic space with time dependent radii. We show that the resultant (p+1)+1(p+1)+1 dimensional metrics describe transient accelerating cosmologies for all pp from 1 to 6, i.e., from (2+1)(2+1) to (7+1)(7+1) space-time dimensions. We show how the acceleration changes with the interplay of the various parameters characterizing the solutions in (3+1)(3+1) dimensions. Finally, for ττ0\tau \ll \tau_0, after compactification on (8p)(8-p) dimensional hyperbolic space, the resultant metrics are shown to take the form of (p+1)+1(p+1)+1 dimensional de Sitter spaces upto a conformal transformation. Cosmologies here are decelerating, but, only in a particular conformal frame we get eternal acceleration.

Keywords

Cite

@article{arxiv.1411.2444,
  title  = {Space-like Dp branes: accelerating cosmologies versus conformally de Sitter space-time},
  author = {Kuntal Nayek and Shibaji Roy},
  journal= {arXiv preprint arXiv:1411.2444},
  year   = {2015}
}

Comments

18 pages, 7 figures; v2: major revision, accelerating cosmologies obtained for all $p$, paper has been corrected accordingly, figures improved; v3: typos fixed, minor changes and more clarifications added, version to appear in JHEP

R2 v1 2026-06-22T06:53:30.110Z