Locality in quantum gravity and string theory

TL;DR

This paper investigates the breakdown of local physics in string theory and gravitational contexts, examining ultrahigh-energy scattering to understand nonlocality and its implications for black hole information loss.

Contribution

It provides a comprehensive analysis of nonlocality in string theory and gravity, highlighting where local quantum field theory fails at gravitational scales.

Findings

No evidence of nonlocality from strings growing linearly with energy

Local quantum field theory fails at gravitationally determined scales

Nonlocality may be key to resolving black hole information paradox

Abstract

Breakdown of local physics in string theory at distances longer than the string scale is investigated. Such nonlocality would be expected to be visible in ultrahigh-energy scattering. The results of various approaches to such scattering are collected and examined. No evidence is found for non-locality from strings whose length grows linearly with the energy. However, local quantum field theory does apparently fail at scales determined by gravitational physics, particularly strong gravitational dynamics. This amplifies locality bound arguments that such failure of locality is a fundamental aspect of physics. This kind of nonlocality could be a central element of a possible loophole in the argument for information loss in black holes.