Axion monodromy inflation with multi-natural modulations
  We study parameter space in the axion monodromy inflation corrected by dynamically generated terms involving with the axion. The potential has the linear potential with multiple sinusoidal functions, which play a role in generating modulations. We show that this potential leads both to a large tensor-to-scalar ratio $r_T \sim 0.16$ and to a large negative running of spectral index $\alpha_s \sim - (0.02 -0.03)$. To realize these results, a small hierarchy among dynamical scales is required whereas the decay constants in sinusoidal functions remain sub-Planckian in this model. We discuss also reheating process after the inflation in a bottom-up approach. 
Tetsutaro Higaki, Tatsuo Kobayashi, Osamu Seto, and Yuya Yamaguchi
hep-ph astro-ph.CO hep-th