Emergent General Relativity

TL;DR

This paper reviews various emergent spacetime models in quantum gravity, compares different approaches to time, and introduces a novel method called Internal Relativity where Einstein's equations are derived rather than assumed.

Contribution

It proposes a new approach called Internal Relativity that derives Einstein's equations, advancing the understanding of emergent spacetime in quantum gravity.

Findings

Different approaches to quantum gravity treat time differently.

Internal Relativity derives Einstein's equations from underlying principles.

Comparison of Volovik and Lloyd's proposals on emergent spacetime.

Abstract

We review different approaches to quantum gravity in which spacetime is emerging. We discuss in some detail the proposals by G. Volovik and S. Lloyd and show how they differ in the way they treat time. We further propose an approach to quantum gravity in which the Einstein equations are derived rather then used. We call this approach Internal Relativity.