Comments on quantum gravity and entanglement

TL;DR

This paper explores how quantum entanglement influences the emergence of spacetime in quantum gravity, suggesting that connected spacetimes can be superpositions of disconnected quantum states.

Contribution

It provides insights into the non-perturbative structure of quantum gravity using gauge-theory/gravity duality and emphasizes the role of entanglement in spacetime emergence.

Findings

Entanglement is crucial for the emergence of spacetime.

Classically connected spacetimes can be superpositions of disconnected states.

Spacetime patches correspond to states in quantum systems.

Abstract

In this note, we attempt to provide some insights into the structure of non-perturbative descriptions of quantum gravity using known examples of gauge-theory / gravity duality. We argue that in familiar examples, a quantum description of spacetime can be associated with a manifold-like structure in which particular patches of spacetime are associated with states or density matrices in specific quantum systems. We argue that quantum entanglement between microscopic degrees of freedom plays an essential role in the emergence of a dual spacetime from the nonperturbative degrees of freedom. In particular, in at least some cases, classically connected spacetimes may be understood as particular quantum superpositions of disconnected spacetimes.