String-Inspired Infinite-Derivative Theories of Gravity: A Brief Overview

TL;DR

This paper reviews recent progress in string-inspired infinite-derivative gravity theories, which aim to resolve singularities and ultraviolet issues without ghosts, highlighting their theoretical development and general results.

Contribution

It provides a concise overview of the construction and properties of infinite-derivative gravity theories inspired by string theory, emphasizing their potential to address gravity singularities.

Findings

Infinite-derivative theories can tame ultraviolet divergences.

Such theories may resolve classical singularities in gravity.

General results apply to covariant torsion-free metric theories.

Abstract

In String Theory there often appears a rather interesting class of higher derivative theories containing an infinite set of derivatives in the form of an exponential. These theories may provide a way to tame ultraviolet divergences without introducing ghost-like states. In this invited article we provide a brief overview on the progress that has been made over the last decade to construct such infinite derivative theories of gravity which may be able to address the singularity problems in gravity. In the process we will also be able to present some general results that applies to covariant torsion-free metric theories of gravity.