Numerical evaluation of inflationary 3-point functions on curved field space

Butchers, Sean and Seery, David (2018) Numerical evaluation of inflationary 3-point functions on curved field space. Journal of Cosmology and Astroparticle Physics, 2018 (07). 031. ISSN 1475-7516

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We extend the public CppTransport code to calculate the statistical properties of fluctuations in multiple-field inflationary models with curved field space. Our implementation accounts for all physical effects at tree-level in the 'in-in' diagrammatic expansion. This includes particle production due to time-varying masses, but excludes scenarios where the curvature perturbation is generated by averaging over the decay of more than one particle. We test our implementation by comparing results in Cartesian and polar field-space coordinates, showing excellent numerical agreement and only minor degradation in compute time. We compare our results with the PyTransport 2.0 code, which uses the same computational approach but a different numerical implementation, finding good agreement. Finally, we use our tools to study a class of gelaton-like models which could produce an enhanced non-Gaussian signal on equilateral configurations of the Fourier bispectrum. We show this is difficult to achieve using hyperbolic field-space manifolds and simple inflationary potentials.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
School of Psychology > Psychology
Research Centres and Groups: Astronomy Centre
Subjects: Q Science > QB Astronomy > QB0980 Cosmogony. Cosmology
Depositing User: Sean Butchers
Date Deposited: 18 Jul 2018 15:40
Last Modified: 16 Jul 2019 01:00

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Project NameSussex Project NumberFunderFunder Ref
Precisions tests of the inflationary scenarioG0918EUROPEAN UNION308082