Multi-field inflation from holography

TL;DR

This paper explores multi-field inflation through holography, linking bulk scalar fields to boundary operators, and analyzes how entropy perturbations influence the conservation of curvature perturbations.

Contribution

It introduces a holographic framework for multi-field inflation and computes power spectra, highlighting the conditions under which curvature perturbations are conserved.

Findings

Adiabatic perturbation is not conserved with entropy perturbations.

Conservation occurs when entropy perturbations are zero or in single-field models.

The model aligns with standard cosmological perturbation theory expectations.

Abstract

We initiate the study of multi-field inflation using holography. Bulk light scalar fields correspond to nearly marginal operators in the boundary theory and the dual quantum field theory is a deformation of a CFT by such operators. We compute the power spectra of adiabatic and entropy perturbations in a simple model and find that the adiabatic curvature perturbation is not conserved in the presence of entropy perturbations but becomes conserved when the entropy perturbations are set to zero or the model is effectively a single scalar model, in agreement with expectations from cosmological perturbation theory.