On Non-Gaussianities in Two-Field Poly-Instanton Inflation

TL;DR

This paper explores two-field poly-instanton inflation in Type IIB string theory, revealing that non-Gaussianities are negligible during slow-roll but become significant beyond slow-roll, with multiple inflationary trajectories analyzed.

Contribution

It introduces a two-field generalization of poly-instanton inflation including axion moduli, and studies the resulting non-Gaussianities across different inflationary regimes.

Findings

Non-Gaussianities are small during slow-roll inflation.

Non-Gaussianities are significantly enhanced in the beyond slow-roll regime.

Multiple inflationary trajectories can produce over 50 e-foldings.

Abstract

In the context of Type IIB LARGE volume orientifold setup equipped with poly-instanton corrections, the standard single-field poly-instanton inflation driven by a 'Wilson' divisor volume modulus is generalized by the inclusion of respective axion modulus. This two-field dynamics results in a "Roulette" type inflation with the presence of several inflationary trajectories which could produce 50 (or more) e-foldings. The evolution of various trajectories along with physical observables are studied. The possibility of generating primordial non-Gaussianities in the slow-roll as well as in the beyond slow-roll region is investigated. We find that although the non- linearity parameters are quite small during the slow-roll regime, the same are significantly enhanced in the beyond slow-roll regime investigated up to the end of inflation.