Planck scale operators, inflation and fine tuning

TL;DR

This paper explores how treating all Planck scale operators equally and applying fine-tuning can address issues in inflationary models within quantum gravity, despite the challenges of nonrenormalizability and unitarity.

Contribution

It proposes a democratic treatment of Planck scale operators combined with fine-tuning to achieve viable inflationary conditions.

Findings

Fine-tuning allows slow roll inflation despite many operators.

Treating operators democratically helps manage undesirable features.

Viable inflation persists even with numerous Planck scale operators.

Abstract

Ultraviolet completion of the standard model plus gravity at and beyond the Planck scale is a daunting problem to which no generally accepted solution exists. Principal obstacles include (a) lack of data at the Planck scale (b) nonrenormalizability of gravity and (c) unitarity problem. Here we make a simple observation that, if one treats all Planck scale operators of equal canonical dimension democratically, one can tame some of the undesirable features of these models. With a reasonable amount of fine tuning one can satisfy slow roll conditions required in viable inflationary models. That remains true even when the number of such operators becomes very large.