Loop Corrections to Cosmological Perturbations in Multi-field Inflationary Models

TL;DR

This paper analyzes one-loop quantum corrections to the power spectrum in multi-field DBI inflation, revealing that non-canonical kinetic terms can significantly enhance these corrections, which are also IR finite.

Contribution

It provides a detailed calculation of loop corrections in multi-DBI inflation, highlighting the effects of non-canonical kinetic terms and entropy-adiabatic interactions.

Findings

Loop corrections are enhanced by slow-varying parameters and small sound speed.

Loop corrections from cross-interactions are IR finite.

Corrections can be large in multi-DBI models.

Abstract

We investigate one-loop quantum corrections to the power spectrum of adiabatic perturbation from entropy modes/adiabatic mode cross-interactions in multiple DBI inflationary models. We find that due to the non-canonical kinetic term in DBI models, the loop corrections are enhanced by slow-varying parameter $\epsilon$ and small sound speed $c_s$. Thus, in general the loop-corrections in multi-DBI models can be large. Moreover, we find that the loop-corrections from adiabatic/entropy cross-interaction vertices are IR finite.