Forthcoming missions probing the absolute intensity of the CMB are expected
to be able to measure spectral distortions, which are deviations from its
blackbody distribution. As cosmic inflation can induce spectral distortions,
these experiments offer a possibility to further test the various promising
inflationary proposals, whose predictions need to be carefully determined.
After numerically fitting all inflationary observables to match current
observations, we compute the predicted spectral distortions of various
promising single and multifield inflationary models. The predictions of
single-field inflationary models display deviations between 1% and 20% with
respect to the standard cosmological model in the observable window, where
multi-natural and axion-monodromy inflation stand out in this respect. In the
case of multifield inflation, we observe a richer structure of the power
spectrum, which, in the case of so-called hybrid attractors, yields spectral
distortions about 100 times more intense than the standard signal. These
observations open up questions about the relation among our results and other
cosmological observables that are also to be probed soon.Comment: 30 pages + references, 17 figures, 6 table