Bound on largest $r\lesssim 0.1$ from sub-Planckian excursions of inflaton

摘要: In this paper we will discuss the range of large tensor to scalar ratio, $r$, obtainable from a sub-Planckian excursion {\it single}, slow roll} driven inflaton field. order obtain $r$ for such scenario one has depart monotonic evolution roll parameters in way that still satisfies all current constraints \texttt{Planck}, as amplitude, tilt power spectrum, running and close pivot scale. Since evolve non-monotonically, also consider spectrum on smallest scales, i.e. at ${\cal P}_{s}(k\sim 10^{16}~{\rm Mpc^{-1}})\lesssim 10^{-2}$, make sure amplitude does not become too large. All these tend keep $r\lesssim 0.1$. We scan three different kinds potential supersymmetric flat directions benchmark points which satisfy constraints. show it is possible go beyond $r\gtrsim 0.1$ provided relax upper bound scales.