Helical Phase Inflation

TL;DR

This paper proposes a natural supergravity model for quadratic inflation using the phase of a complex field with a helicoid potential, addressing the eta problem and UV sensitivity.

Contribution

It introduces a novel supergravity realization of phase inflation with a helicoid potential, providing a new approach to large field inflation and monodromy inflation in supersymmetry.

Findings

Realizes quadratic inflation via the phase of a complex field.

Addresses the eta problem through a flat direction from U(1) symmetry.

Provides a UV-insensitive, natural inflation model in supergravity.

Abstract

We show that the quadratic inflation can be realized by the phase of a complex field with helicoid potential. Remarkably, this helicoid potential can be simply realized in minimal supergravity. The global $U(1)$ symmetry of the K\"ahler potential introduces a flat direction and evades the $\eta$ problem automatically. So such inflation is technically natural. The phase excursion is super-Planckian as required by the Lyth bound, while the norm of the complex field can be suppressed in the sub-Planckian region. This model resolves the ultraviolet sensitive problem of the large field inflation, besides, it also provides a new type of monodromy inflation in supersymmetric field theory with consistent field stabilization.