Multi-Natural Inflation in Supergravity and BICEP2

Understand

We revisit the recently proposed multi-natural inflation and its realization in supergravity in light of the BICEP2 results.

• Multi-natural inflation is a single-field inflation model where the inflaton potential consists of multiple sinusoidal functions, and it is known that a sizable running spectral index can be generated, which relaxes the tension between the BICEP2 and the Planck results.
• In this paper we show that multi-natural inflation can accommodate a wide range of values of $(n_s, r)$, including the spectral index close to or even above unity.
• This will be be favored if the tension is resolved by other sources such as dark radiation, hot dark matter, or non-zero neutrino mass.