CMB probes on the correlated axion isocurvature perturbation

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. c 2015 IOP Publishing Ltd and Sissa Medialab srl