Frontiers in Physics (Jan 2015)
Perspective on completing natural inflation
Abstract
We present a perspective on the inflation paths in $2-, 3-, cdots, N-$flation models based on the ultraviolet completion in heterotic string theory, where a number of grand unification scale axions are used. The number of non-Abelian gauge groups for a natural inflation is restricted in string compactification, and we argue that the most plausible completion of natural inflation from a theory perspective is the 2-- and 3--flation.
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