Inflationary trispectrum from graviton exchange
By D. Seery, M. Sloth, F. Vernizzi. 2008
226 citations recorded by the source corpus.
We compute the connected four-point correlation function of the primordial curvature perturbation generated during inflation with standard kinetic terms, where the correlation is established via exchange of a graviton between two pairs of scalar fluctuations. Any such correlation yields a contribution to the scalar trispectrum of the order of the tensor to scalar ratio r. This contribution is numerically one order of magnitude larger than the one previously calculated on the basis of scalar perturbations interacting at a point and satisfies a simple relation in the limit where the momentum of the graviton which is exchanged becomes much smaller than the external momenta. We conclude that the total non-linearity parameter generated by single-field models of slow-roll inflation is at maximum |tNL| ~ r.
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/9efb4b529553786eb75a5d9416a7c2434a0595eb
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Citations in the corpus
- An infinite set of Ward identities for adiabatic modes in cosmology (2013, background): “In this limit, the correlation function is dominated by the exchange of a soft scalar or tensor mode, and the answer factorizes into the product of N −M + 1- and M + 1-point correlators in the soft limit [68, 69].”
- Galileon inflation (2010, background): “[49, 67] one should define this limit by analytic continuation, first carrying out the integral with θ3 > 0 and only subsequently squeezing one of the momenta to zero.”
- The Cosmological Optical Theorem (2020, background): “In particular, we discuss the primordial trispectrum arising from the inflaton self-coupling in the Effective Field Theory of inflation [29] and from graviton exchange [38].”
- Sachs-Wolfe at second order: the CMB bispectrum on large angular scales (2009, background): “An analogous effect is found when computing the contribution to the scalar trispectrum from graviton exchange [43].”
- The cosmological bootstrap: inflationary correlators from symmetries and singularities (2018, unknown): “Graviton exchange The leading four-point function in single-field slow-roll inflation arises from graviton exchange [99] (see also [33, 100, 101]).”
- Quasi-Single Field Inflation and Non-Gaussianities (2009, background): “Cases of such UV spurious divergences are encountered, for example, in the study of trispectra [8–11] if one uses the commutator form.”
- Building a boostless bootstrap for the bispectrum (2020, background): “This is not the trispectrum from the exchange of a transverse-traceless graviton computed in the in-in formalism in [97], which does not contribute to the soft trispectrum.”
- Bootstrapping inflationary correlators in Mellin space (2019, background): “26) of [123].”
- Infrared effects in inflationary correlation functions (2010, background): “The distinction has been maintained in equation (24) because in practical calculations one must often calculate off-shell where k1 = k2, only taking the on-shell limit at the end of the calculation [15, 44, 60, 96]; the same is true for higher npoint functions where one must keep the ki all distinct”
- Conformal consistency relations for single-field inflation (2012, background): “(72) We can see that our results allow to capture also the O(q) corrections in the counter-collinear limit, and this is exactly the result that one finds taking the appropriate limit of the full 4-point function induced by the graviton exchange [20].”