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Magnon inflation: slow roll with steep potentials

Adshead, Peter
Blas, Diego
Burgess, C.P.
Hayman, Peter
Published in Journal of Cosmology and Astroparticle Physics. 2016, vol. 1611, no. 11, p. 009
Collection Open Access - SCOAP3
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 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.
Keywords InflationParticle physics - cosmology connection
arXiv: 1604.06048
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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 https://archive-ouverte.unige.ch/unige:89835

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Deposited on : 2016-12-05

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