CMB probes on the correlated axion isocurvature perturbation
  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. 
Kenji Kadota, Jinn-Ouk Gong, Kiyotomo Ichiki, Takahiko Matsubara
astro-ph.CO gr-qc hep-ph hep-th