Circumventing the eta problem in building an inflationary model in string theory

Damien Easson, Ruth Gregory

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


The eta problem is one of the most significant obstacles to building a successful inflationary model in string theory. Planck mass suppressed corrections to the inflaton potential generally lead to inflaton masses of order the Hubble scale and generate contributions of order unity to the η slow-roll parameter rendering prolonged slow-roll inflation impossible. We demonstrate the severity of this problem in the context of brane antibrane inflation in a warped throat of a Calabi-Yau flux compactification with all phenomenologically dangerous moduli stabilized. Using numerical solutions we show that the eta problem can be avoided in scenarios where the inflaton is nonminimally coupled to gravity and has Dirac-Born-Infeld kinetic term. We show that the resulting cosmic microwave background observables such as measures of non-Gaussianites can, in principle, serve as a probe of scalar-gravity couplings.

Original languageEnglish (US)
Article number083518
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number8
StatePublished - Oct 15 2009

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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