Slow-roll parameters in braneworld cosmologies

Abstract

We present a general slow-roll formalism within braneworld-motivated cosmologies with non-standard effective Friedmann equations. Full towers of parameters involving either the inflaton potential or the Hubble parameter are constructed and the dynamics of non-tachyonic and tachyonic fields are considered in detail; exact cosmological solutions and the inflationary attractor condition are provided. We compare scalar-driven and tachyon-driven accelerating eras through slow-roll correspondence and the observational imprint on early-universe structures.

Comments: 28 pages REVTeX4, 4 figures; v2: new figures and comments, references added, the content of Appendix A has been moved into the main text. Accepted by Physical Review D