Monodromy Inflation in the Strong Coupling Regime of the Effective Field Theory.

Guido D’Amico,Nemanja Kaloper,Albion Lawrence

doi:10.1103/physrevlett.121.091301

Abstract

We present a simple effective field theory formulation of a general family of single-field flux monodromy models for which strong coupling effects at large field values can flatten the potential and activate higher-derivative operators. Both of these effects can suppress the tensor amplitude. These models are radiatively and nonperturbatively stable and can sustain ≳60 e folds of inflation. The dynamics combines features of both large-field chaotic inflation and k inflation. Reducing the tensor-scalar ratio below the observational bound r≲0.1 while keeping the scalar spectral index n_{s} within experimental bounds either yields equilateral non-Gaussianity f_{NL}^{eq}≃O(1), close to the current observational bounds, or gives very small r.

Highlights

Models of inflation with super-Planckian inflaton ranges can be remarkably simple and predictive [1,2]
Two of us proposed that generic monodromy inflation models have a simple field theory formulation based on a massive 4-form gauge theory [7]
Strong coupling provides at least two significant effects: nontrivial “flattened” potentials as seen in string theory constructions [3,4,13,14], and higher-derivative terms such as those in k inflation [15,16]

Summary

Introduction

Models of inflation with super-Planckian inflaton ranges can be remarkably simple and predictive [1,2]. Strong coupling provides at least two significant effects: nontrivial “flattened” potentials as seen in string theory constructions [3,4,13,14], and higher-derivative terms such as those in k inflation [15,16]. The higher-derivative terms are dynamically suppressed, and inflation is the standard potential-driven slow roll.

Results

Conclusion