Can CMB data constrain the inflationary field range?

2014/05/31 by Juan Garcia-Bellido, Diederik Roest, Marco Scalisi +1 · 1 citation
Physics and Astronomy · #hep-th #astro-ph.CO #gr-qc #hep-ph

paper · pdf · doi:10.1088/1475-7516/2014/09/006

published as JCAP09(2014)006 · 15 pages, 7 figures. v2: minor typos corrected, refs added, JCAP version

arxiv created 2014/09/04 · arxiv updated 2014/09/08

Abstract

We study to what extent the spectral index n_s and the tensor-to-scalar ratio r determine the field excursion Δϕ during inflation. We analyse the possible degeneracy of Δϕ by comparing three broad classes of inflationary models, with different dependence on the number of e-foldings N, to benchmark models of chaotic inflation with monomial potentials. The classes discussed cover a large set of inflationary single field models. We find that the field range is not uniquely determined for any value of (n_s, r); one can have the same predictions as chaotic inflation and a very different Δϕ. Intriguingly, we find that the field range cannot exceed an upper bound that appears in different classes of models. Finally, Δϕ can even become sub-Planckian, but this requires to go beyond the single-field slow-roll paradigm.

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