Can the latent signatures of quantum superposition be detected through correlation harvesting?

TL;DR

This paper investigates how quantum superposition of spacetime affects correlation harvesting, revealing enhanced entanglement and mutual information under certain conditions using Unruh-DeWitt detectors in a superposed BTZ black hole spacetime.

Contribution

It demonstrates that superposed spacetime can significantly enhance correlation harvesting, especially entanglement, due to constructive interference effects.

Findings

Superposed spacetime enhances entanglement harvesting compared to single spacetime.

Mutual information depends on detector separation and mass ratios, with maxima aligned with initial spacetime.

Correlation harvesting peaks when the superposition state matches the initial spacetime state.

Abstract

In this paper, we explore correlation harvesting in quantum superposition, specifically focusing on the entanglement and mutual information extracted by two Unruh-DeWitt detectors interacting with a quantum field in a mass-superposed BTZ black hole spacetime. Our findings reveal that the superposed nature of spacetime induces constructive interference between the field modes that can significantly enhance the entanglement harvesting relative to a single spacetime background. In contrast to entanglement, the mutual information obtained in spacetime superposition is influenced by the proper distance between the two detectors. While the mutual information harvested in a superposed spacetime remains lower than that in a single spacetime when the proper distance between detectors is small, it exceeds that in a single spacetime for specific mass ratios as the distance increases. Notably, we find that both entanglement and mutual information harvesting reach their maxima when the final spacetime superposition state is conditioned to align with the initial spacetime state.