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

Abstract

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.

25 pages, 11 figures + 17 page appendix and references

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Cited by in corpus (11)

• Dissecting the growth of the power spectrum for primordial black holes
• Hyper non-Gaussianities in inflation with strongly non-geodesic motion
• A manifestly covariant theory of multifield stochastic inflation in phase space: solving the discretisation ambiguity in stochastic inflation
• Revisiting non-Gaussianity in multifield inflation with curved field space
• Flattened non-Gaussianities from the effective field theory of inflation with imaginary speed of sound
• Multifield inflation beyond $N_{\mathrm{field}}=2$: non-Gaussianities and single-field effective theory
• Pole N-flation
• Probing Inflation with Precision Bispectra
• Non-Gaussianity after many-field reheating
• Non-Gaussianity in D3-brane inflation
• Inflationary $\alpha$-Attractor From Type IIB/F Theory