Large non-Gaussianities in the Effective Field Theory Approach to Single-Field Inflation: the Trispectrum

Article
Report number	arXiv:1006.5411 ; CERN-PH-TH-2010-146
Title	Large non-Gaussianities in the Effective Field Theory Approach to Single-Field Inflation: the Trispectrum
Author(s)	Bartolo, Nicola (Padua U. ; INFN, Padua) ; Fasiello, Matteo (Milan Bicocca U. ; INFN, Milan Bicocca) ; Matarrese, Sabino (Padua U. ; INFN, Padua) ; Riotto, Antonio (INFN, Padua ; CERN)
Publication	2010
Imprint	29 Jun 2010
Number of pages	29 p, 29
Note	Comments: 29 pages, 13 figures
In:	JCAP 09 (2010) 035
DOI	10.1088/1475-7516/2010/09/035
Subject category	Astrophysics and Astronomy
Abstract	We perform the analysis of the trispectrum of curvature perturbations generated by the interactions characterizing a general theory of single-field inflation obtained by effective field theory methods. We find that curvature-generated interaction terms, which can in general give an important contribution to the amplitude of the four-point function, show some new distinctive features in the form of their trispectrum shape-function. These interesting interactions are invariant under some recently proposed symmetries of the general theory and, as shown explicitly, do allow for a large value of the trispectrum.
Copyright/License	Preprint: © 2010-2024 CERN (License: CC-BY-3.0)

$The \textit{equilateral} configuration shape is presented on the left from the scalar exchange contribution of the $\bar M_6$-driven interaction. The shape-function is different from the plots presented in \cite{chen-tris}. On the other hand, once a necessary change of variables has been performed, it is qualitatively similar to the shape for the contact interaction diagram which arises from the ghost inflation $(\nabla \pi)^4$ interaction term in \cite{muko}.\\ On the right we plotted our findings for the $\bar M_6$-generated interaction in the \textit{folded} configuration. It very much resembles the ones obtained in \cite{chen-tris} for the scalar exchange diagrams from DBI-like terms, especially from the interaction $\dot \pi (\nabla \pi)^2$ . In all the pictures above and below $k_1$ has ben set equal to unity without loss of generality.$ $The \textit{equilateral} configuration shape is presented on the left from the scalar exchange contribution of the $\bar M_6$-driven interaction. The shape-function is different from the plots presented in \cite{chen-tris}. On the other hand, once a necessary change of variables has been performed, it is qualitatively similar to the shape for the contact interaction diagram which arises from the ghost inflation $(\nabla \pi)^4$ interaction term in \cite{muko}.\\ On the right we plotted our findings for the $\bar M_6$-generated interaction in the \textit{folded} configuration. It very much resembles the ones obtained in \cite{chen-tris} for the scalar exchange diagrams from DBI-like terms, especially from the interaction $\dot \pi (\nabla \pi)^2$ . In all the pictures above and below $k_1$ has ben set equal to unity without loss of generality.$ $On the left the plot obtained for the $\bar M_6$ interaction in the \textit{planar} configuration plot. Note here some of the interesting features: as $k_2,k_4 \rightarrow 0$ the shape function goes to zero, much like it happens for DBI-generated interactions. As $k_2,k_4 \rightarrow 2$ the shape function reaches values that are negative, albeit slightly so. Looking at the $k_2 = k_4$ line we see that it is convex, rather than concave as found for other interaction types in \cite{chen-tris}\\ On the right the \textit{planar limit double squeezed configuration} is plotted. In the region of interest, namely for $k_{12} \rightarrow 0$, the shape function is non-zero, finite and negative; this again is different than what found in \cite{chen-tris} for a variety of DBI-originated terms.$ Show more plots

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Record created 2010-06-29, last modified 2023-03-15

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