A violation of global symmetries from replica wormholes and the fate of black hole remnants

TL;DR

The paper demonstrates that replica wormholes cause non-perturbative violations of global charge conservation in quantum gravity, impacting black hole remnants and suggesting emergent global symmetries in holography.

Contribution

It reveals how replica wormholes lead to global symmetry violations and explores implications for black hole remnants and holographic dualities.

Findings

Replica wormholes cause non-zero charge transition probabilities.

Global charge conservation is violated non-perturbatively.

Emergent global symmetries appear after ensemble averaging in holography.

Abstract

We show that the presence of replica wormholes in the Euclidean path integral of gravity leads to a non-perturbative violation of charge conservation for any global symmetry present in the low-energy description of quantum gravity. Explicitly, we compute the scattering probability between different charged states in several two-dimensional models of quantum gravity and find a non-vanishing answer. This suggests that the set of all charged states is typically over-complete, which has drastic consequences for the fate of black hole remnants that could carry a global symmetry charge. In the holographic context, we argue that the presence of such a symmetry in the effective description of the bulk should appear on the boundary as an emergent global symmetry after ensemble averaging.