Towards axionic Starobinsky-like inflation in string theory

Abstract

It is shown that Starobinsky-like potentials can be realized in non-geometric flux compactifications of string theory, where the inflaton involves an axion whose shift symmetry can protect UV-corrections to the scalar potential. For that purpose we evaluate the backreacted, uplifted F-term axion-monodromy potential, which interpolates between a quadratic and a Starobinsky-like form. Limitations due to the requirements of having a controlled approximation of the UV theory and of realizing single-field inflation are discussed.

Helical phase inflation via non-geometric flux compactifications: from natural to starobinsky-like inflation

“…(3.1) is significantly smaller than the other terms so that we can safely integrate them out. In contrast, in our proposal the non-geometric fluxes lead to much more complex constraints than those in [58]. We expect the constraints from the flux Jacobi identities and Minkowski vacuum conditions can be solved numerically.…”

“…It is interesting to compare our proposal with the work in [58], which also studied the Starobinsky-like inflation based on non-geometric flux compactification. In [58] the inflaton is from string moduli which strongly interact with other heavy fields, so it needs to adjust the parameters carefully so that the inflation direction is sufficient flat while all the extra fields are at or above Hubble scale.…”

“…Starobinsky-like inflation with a string-theoretic embedding has been studied in refs. [55][56][57][58]. Another interesting solution is the realization of Starobinsky-like inflation within the…”

“…In [58] the inflaton is from string moduli which strongly interact with other heavy fields, so it needs to adjust the parameters carefully so that the inflation direction is sufficient flat while all the extra fields are at or above Hubble scale. Because for large field inflation a super-Planckian field excursion is required and the inflation dynamics is rather sensitive to the super-Planckian physics, one also needs to check whether the large field inflation can be reasonably studied in the low energy effective theory.…”

“…Because for large field inflation a super-Planckian field excursion is required and the inflation dynamics is rather sensitive to the super-Planckian physics, one also needs to check whether the large field inflation can be reasonably studied in the low energy effective theory. In particular the following hierarchy should be unbroken under super-Planckian string moduli/axion field excursion [58] …”