Cosmological perturbations from multi-field inflation

TL;DR

This paper reviews the derivation of cosmological perturbation spectra in simple inflation models and extends the formalism to multi-field scenarios, including multi-field DBI inflation, highlighting the effects of multiple scalar fields.

Contribution

It introduces a general formalism for analyzing cosmological perturbations in multi-field inflation models with arbitrary kinetic term dependence, including specific case studies.

Findings

General formalism for multi-field inflation perturbations

Application to multi-field DBI inflation

Insights into the impact of multiple fields on perturbation spectra

Abstract

We briefly review the standard derivation of the spectra of cosmological perturbations in the simplest models of inflation. We then consider models with several scalar fields, described by Lagrangians with an arbitrary dependence on the kinetic terms. We illustrate our general formalism with the case of multi-field DBI inflation.