Emergence of string-like physics from Lorentz invariance in loop quantum gravity

TL;DR

This paper shows that in loop quantum gravity, to preserve Lorentz invariance, quantum fields must have non-local interactions akin to string theory, indicating a link between these theories.

Contribution

It demonstrates that Lorentz invariance preservation in loop quantum gravity requires non-local interactions similar to string theory, revealing a novel connection between the two frameworks.

Findings

Non-local interactions are necessary to avoid Lorentz violations

Loop quantum gravity constrains matter field interactions

Signs of string-like physics emerge from quantum gravity considerations

Abstract

We consider a quantum field theory on a spherically symmetric quantum space time described by loop quantum gravity. The spin network description of space time in such a theory leads to equations for the quantum field that are discrete. We show that to avoid significant violations of Lorentz invariance one needs to consider specific non-local interactions in the quantum field theory similar to those that appear in string theory. This is the first sign that loop quantum gravity places restrictions on the type of matter considered, and points to a connection with string theory physics.