CMB probes on the correlated axion isocurvature perturbation

TL;DR

This paper investigates how future CMB polarization and lensing data can detect the gravitational coupling effects between the inflaton and axion-like fields, focusing on their cross-correlation in cosmological perturbations.

Contribution

It introduces a detailed analysis of the scale-dependent cross-correlation power spectrum between curvature and axion isocurvature perturbations influenced by axion parameters.

Findings

Sensitivity estimates for upcoming CMB data on axion-induced correlations.

Explicit dependence of the cross-correlation spectrum on axion parameters.

Potential to constrain axion models with future CMB observations.

Abstract

We explore the possible cosmological consequence of the gravitational coupling between the inflaton and axion-like fields. In view of the forthcoming cosmic microwave background (CMB) polarization and lensing data, we study the sensitivity of the CMB data on the cross-correlation between the curvature and axion isocurvature perturbations. Through a concrete example, we illustrate the explicit dependence of the scale dependent cross-correlation power spectrum on the axion parameters.