Chaotic inflation on the brane

Roy Maartens, David Wands, Bruce A. Bassett, Imogen P. C. Heard

Research output: Contribution to journalArticlepeer-review


We consider slow-roll inflation in the context of recently proposed four-dimensional effective gravity induced on the world-volume of a three-brane in five-dimensional Einstein gravity. We find significant modifications of the simplest chaotic inflationary scenario when the five-dimensional Planck scale is below about 1017 GeV. We use the comoving curvature perturbation, which remains constant on super-Hubble scales, in order to calculate the spectrum of adiabatic density perturbations generated. Modifications to the Friedmann constraint equation lead to a faster Hubble expansion at high energies and a more strongly damped evolution of the scalar field. This assists slow-roll, enhances the amount of inflation obtained in any given model, and drives the perturbations towards an exactly scale-invariant Harrison-Zel’dovich spectrum. In chaotic inflation driven by a massive scalar field we show that inflation can occur at field values far below the four-dimensional Planck scale, though above the five-dimensional fundamental scale.
Original languageEnglish
Article number041301
Pages (from-to)041301
JournalPhysical Review D
Issue number4
Publication statusPublished - 15 Aug 2000


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