Some Remarks on the Semi-Classical Limit of Quantum Gravity

TL;DR

This paper explores defining and understanding the semi-classical regime of quantum gravity, proposing approaches using effective theories on flat backgrounds and background-independent quantum information methods.

Contribution

It introduces a framework for characterizing the semi-classical limit of quantum gravity through effective theories and quantum information techniques.

Findings

Non-commutative spacetime in deformed special relativity as an effective arena

Background-independent formulation via quantum information and renormalization

Clarification of semi-classical regime definition in quantum gravity

Abstract

One of the most important issues in quantum gravity is to identify its semi-classical regime. First the issue is to define for we mean by a semi-classical theory of quantum gravity, then we would like to use it to extract physical predictions. Writing an effective theory on a flat background is a way to address this problem and I explain how the non-commutative spacetime of deformed special relativity is the natural arena for such considerations. On the other hand, I discuss how the definition of the semi-classical regime can be formulated in a background independent fashion in terms of quantum information and renormalisation of geometry.