Scientific article
Open access

Magnon inflation: slow roll with steep potentials

Published inJournal of cosmology and astroparticle physics, vol. 1611, no. 11, 009
  • Open Access - SCOAP3
Publication date2016

We find multi-scalar effective field theories (EFTs) that can achieve a slow inflationary roll despite having a scalar potential that does not satisfy 𝒢ab ∂a V ∂b V ≪ V2/Mp2 (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.

  • Inflation
  • Particle physics - cosmology connection
Citation (ISO format)
ADSHEAD, Peter et al. Magnon inflation: slow roll with steep potentials. In: Journal of cosmology and astroparticle physics, 2016, vol. 1611, n° 11, p. 009. doi: 10.1088/1475-7516/2016/11/009
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Article (Published version)
ISSN of the journal1475-7516

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