Many alternatives to canonical slow-roll inflation have been proposed over the years, one of the main motivations being to have a model, capable of generating observable values of non-Gaussianity. In this work, we (re-)explore the physical implications of a great majority of such models within a single, effective field theory framework (including novel models with large non-Gaussianity discussed for the first time below.) The constraints we apply---both theoretical and experimental---are found to be rather robust, determined to a great extent by just three parameters: the coefficients of the quadratic EFT operators $(delta N)^2$ and $delta N delta E$, and the slow-roll parameter $arepsilon$. This allows to significantly limit the majority of single-field alternatives to canonical slow-roll inflation. While the existing data still leaves some room for most of the considered models, the situation would change dramatically if the current upper limit on the tensor-to-scalar ratio decreased down to $r < 10^-2$. Apart from inflationary models driven by plateau-like potentials, the single-field model that would have a chance of surviving this bound is the recently proposed slow-roll inflation with weakly-broken galileon symmetry. In contrast to extitcanonical slow-roll inflation, the latter model can support $r < 10^-2$ even if driven by a convex potential, as well as generate observable values for the amplitude of non-Gaussianity.
|Titolo:||Constraints on single-field inflation|
|Data di pubblicazione:||2016|
|Settore Scientifico Disciplinare:||Settore FIS/02 - Fisica Teorica, Modelli e Metodi Matematici|
|Parole Chiave:||High Energy Physics - Theory; High Energy Physics - Theory; astro-ph.CO|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1088/1475-7516/2016/06/051|
|Appare nelle tipologie:|