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Influence of reheating on the trispectrum and its scale dependence

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journal contribution
posted on 2023-06-08, 17:25 authored by Godfrey Leung, Ewan R M Tarrant, Christian ByrnesChristian Byrnes, Edmund J Copeland
We study the evolution of the non-linear curvature perturbation during perturbative reheating, and hence how observables evolve to their final values which we may compare against observations. Our study includes the evolution of the two trispectrum parameters, $\gnl$ and $\taunl$, as well as the scale dependence of both $\fnl$ and $\taunl$. In general the evolution is significant and must be taken into account, which means that models of multifield inflation cannot be compared to observations without specifying how the subsequent reheating takes place. If the trispectrum is large at the end of inflation, it normally remains large at the end of reheating. In the classes of models we study, it is very hard to generate $\taunl\gg\fnl^2$, regardless of the decay rates of the fields. Similarly, for the classes of models in which $\gnl\simeq\taunl$ during slow--roll inflation, we find the relation typically remains valid during reheating. Therefore it is possible to observationally test such classes of models without specifying the parameters of reheating, even though the individual observables are sensitive to the details of reheating. It is hard to generate an observably large $\gnl$ however. The runnings, $
fnl$ and $
taunl$, tend to satisfy a consistency relation $
taunl=(3/2)
fnl$, but are in general too small to be observed for the class of models considered regardless of reheating timescale.

History

Publication status

  • Published

File Version

  • Accepted version

Journal

Journal of Cosmology and Astroparticle Physics

ISSN

1475-7516

Publisher

IOP Publishing

Issue

6

Volume

8

Page range

1-22

Department affiliated with

  • Physics and Astronomy Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2014-05-27

First Open Access (FOA) Date

2014-05-27

First Compliant Deposit (FCD) Date

2014-05-27

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