Eternal inflation disfavored by Planck and BICEP2?

[Chronos]

This paper; http://arxiv.org/abs/1404.4614, Negative running prevents eternal inflation, claims Planck and BICEP2 data favors negative running of the spectral index of curvature perturbations from inflation at the 2 sigma level. It further asserts this is sufficient to preclude eternal inflation.

 

[Mordred]

Interesting article, will be interesting to see how it pans out.

 

[bapowell]

It further asserts this is sufficient to preclude eternal inflation.

Yes, the negative running that seems to be required on superhorizon scales in order to reconcile BICEP2 and Planck implies a maximum amplitude for curvature perturbations on these scales. Meanwhile, eternal inflation requires large density fluctuations that dominate over the classical evolution of the inflaton. These two ideas seem in conflict.