1304.1270 (David H. Lyth)

The CMB asymmetry from inflation    [PDF]

David H. Lyth

Erickcek, Kamionkowski and Carroll have proposed that the hemispherical asymmetry of the CMB could be due to a very large scale perturbation of the field $\phi$ causing the primordial curvature. I show that the asymmetry is too small to agree with observation if $\phi$ is the inflaton of single-field inflation. If instead $\phi$ is a curvaton-type field, the asymmetry is proportional to $\fnl(k)$, and can have the required magnitude and scale-dependence.

View original: http://arxiv.org/abs/1304.1270