Pole Inflation - Shift Symmetry and Universal Corrections

TL;DR

This paper explores how shift symmetry in pole inflation models leads to universal corrections to inflationary predictions, highlighting the role of higher-order poles and string theory effects in shaping the inflationary potential.

Contribution

It demonstrates the universality of lowest-order corrections in pole inflation and connects these to string theory structures, providing insights into potential large-scale power loss.

Findings

Corrections are universal at lowest order in pole inflation.

Higher-order poles can break shift symmetry and affect inflationary predictions.

String loop effects may introduce additional corrections.

Abstract

An appealing explanation for the Planck data is provided by inflationary models with a singular non-canonical kinetic term: a Laurent expansion of the kinetic function translates into a potential with a nearly shift-symmetric plateau in canonical fields. The shift symmetry can be broken at large field values by including higher-order poles, which need to be hierarchically suppressed in order not to spoil the inflationary plateau. The herefrom resulting corrections to the inflationary dynamics and predictions are shown to be universal at lowest order and possibly to induce power loss at large angular scales. At lowest order there are no corrections from a pole of just one order higher and we argue that this phenomenon is related to the well-known extended no-scale structure arising in string theory scenarios. Finally, we outline which other corrections may arise from string loop effects.