Quantum signatures of black hole mass superpositions

TL;DR

This paper introduces an operational framework to detect quantum gravitational effects in superpositions of black hole spacetimes, revealing signatures consistent with quantized black hole mass spectra through detector analysis.

Contribution

It develops a novel method to analyze spacetime superpositions using nonlocal correlations, applying it to black hole mass superpositions and detecting quantum signatures without extra assumptions.

Findings

Detector signatures indicate quantum gravitational effects.

Results support the quantized mass spectrum of black holes.

Framework extends understanding of quantum superpositions in gravity.

Abstract

We present a new operational framework for studying ``superpositions of spacetimes'', which are of fundamental interest in the development of a theory of quantum gravity. Our approach capitalizes on nonlocal correlations in curved spacetime quantum field theory, allowing us to formulate a metric for spacetime superpositions as well as characterizing the coupling of particle detectors to a quantum field. We apply our approach to analyze the dynamics of a detector (using the Unruh-deWitt model) in a spacetime generated by a BTZ black hole in a superposition of masses. We find that the detector exhibits signatures of quantum-gravitational effects corroborating and extending Bekenstein's seminal conjecture concerning the quantized mass spectrum of black holes in quantum gravity. Crucially, this result follows directly from the approach, without any additional assumptions about the black hole mass properties.