Numerically evaluating the bispectrum in curved field-space - with PyTransport 2.0

TL;DR

This paper extends the transport method to compute the bispectrum in multi-field inflation models with curved field-space, providing an open-source implementation and demonstrating its application to complex inflationary scenarios.

Contribution

It introduces a novel extension of the transport framework to curved field-space metrics and provides an open-source code for practical computations.

Findings

Successfully computes bispectrum in curved field-space models

Demonstrates the method on non-trivial inflationary examples

Provides an accessible implementation in PyTransport 2.0

Abstract

We extend the transport framework for numerically evaluating the power spectrum and bispectrum in multi-field inflation to the case of a curved field-space metric. This method naturally accounts for all sub- and super-horizon tree level effects, including those induced by the curvature of the field-space. We present an open source implementation of our equations in an extension of the publicly available PyTransport code. Finally we illustrate how our technique is applied to examples of inflationary models with a non-trivial field-space metric.