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arXiv · 1310.8285

Multifield Inflation after Planck: Isocurvature Modes from Nonminimal Couplings

Katelin Schutz·Evangelos I. Sfakianakis·David I. Kaiser
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Abstract

Recent measurements by the {\it Planck} experiment of the power spectrum of temperature anisotropies in the cosmic microwave background radiation (CMB) reveal a deficit of power in low multipoles compared to the predictions from best-fit $\Lambda$CDM cosmology. The low-$\ell$ anomaly may be explained by the presence of primordial isocurvature perturbations in addition to the usual adiabatic spectrum, and hence may provide the first robust evidence that early-universe inflation involved more than one scalar field. In this paper we explore the production of isocurvature perturbations in nonminimally coupled two-field inflation. We find that this class of models readily produces enough power in the isocurvature modes to account for the \emph{Planck} low-$\ell$ anomaly, while also providing excellent agreement with the other {\it Planck} results.

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Katelin Schutz, Evangelos I. Sfakianakis, David I. Kaiser. 2013-10-30. Multifield Inflation after Planck: Isocurvature Modes from Nonminimal Couplings. https://doi.org/10.1103/physrevd.89.064044

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