Transport equations for the inflationary spectral index

TL;DR

This paper introduces a straightforward method using transport equations to compute how the spectral index evolves on superhorizon scales in multi-field inflation models, demonstrated with various potentials.

Contribution

It provides a novel, efficient approach to track the spectral index evolution in complex inflationary scenarios using transport equations.

Findings

Method effectively computes spectral index evolution.

Demonstrated with multiple inflationary potentials.

Simplifies analysis of superhorizon dynamics.

Abstract

We present a simple and efficient method to compute the superhorizon evolution of the spectral index in multi-field inflationary models, using transport equation techniques. We illustrate the evolution of n_s with time for various interesting potentials.