Magnon inflation: Slow roll with steep potentials

Peter Adshead, Diego Blas, C. P. Burgess, Peter Hayman, Subodh P. Patil

Research output: Contribution to journalArticlepeer-review

Abstract

We find multi-scalar effective field theories (EFTs) that can achieve a slow inflationary roll despite having a scalar potential that does not satisfy GabdaV3bV <C V2/Mp (where Gab is the target-space metric). They evade the usual slow-roll conditions on V because their kinetic energies are dominated by single-derivative terms rather than the usual two-derivative terms. Single derivatives dominate during slow roll and so do not require a breakdown of the usual derivative expansion that underpins calculational control in much of cosmology. The presence of such terms requires some sort of UV Lorentz-symmetry breaking during inflation (besides the usual cosmological breaking). Chromo-natural inflation provides one particular example of a UV theory that can generate the multi-field single-derivative terms we consider, and we argue that the EFT we find indeed captures the slow-roll conditions for its background evolution. We also show that our EFT can be understood as a multi-field generalization of the single-field Cuscuton models. The multi-field case introduces a new feature, however: the scalar kinetic terms define a target-space 2-form, Fab, whose antisymmetry gives new ways for slow roll to be achieved.

Original languageEnglish (US)
Article number009
JournalJournal of Cosmology and Astroparticle Physics
Volume2016
Issue number11
DOIs
StatePublished - Nov 4 2016

Keywords

  • Inflation
  • Particle physics - cosmology connection

ASJC Scopus subject areas

  • Astronomy and Astrophysics

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