BICEP2 in Corpuscular Description of Inflation

Understand

A corpuscular quantum description of inflation shows that there is no fundamental problem with trans-Planckian excursions of the inflaton field up to about 100 Planck masses, with the upper bound coming from the corpuscular quantum effects.

• In this description the r-parameter measures the ratio of occupation numbers of gravitons versus inflatons, which, according to BICEP2, was roughly a half at the time of 60 e-foldings prior to the end of inflation.
• We stress that in non-Wilsonian UV self-completion of gravity any trans-Planckian mode coupled to inflaton is a black hole.
• Unlike the Wilsonian case, their integration-out gives an exponentially-suppressed effect and is unable to prevent trans-Planckian excursions of the inflaton field.