Measurement-induced entanglement entropy of gravitational wave detections

TL;DR

This paper proposes a model to measure entanglement entropy during gravitational wave detection, suggesting bipartite measurements could reveal quantum features of gravity despite single-graviton detection challenges.

Contribution

It introduces a bipartite measurement model for gravitational waves, showing entanglement entropy as a potential signature of gravity's non-classicality.

Findings

Entanglement entropy is a few percent of the mean graviton number.

Bipartite detection can reveal quantum gravity signatures.

Single-point detection signatures are less promising.

Abstract

Research on the projective measurement of gravitons increasingly supports Dysons conclusions that the detection of single gravitons is not physically possible. It is therefore prudent to consider alternative signatures of non-classicality in gravitational wave detections to determine if gravity is quantized. Coincident multiple detector operations make it possible to consider the bipartite measurement-induced entanglement, in the detection process, as a signature of non-classicality. By developing a model of measurement-induced entanglement, based on a fixed number of gravitons for the bipartite system, we demonstrate that the entanglement entropy is on the order of a few percent of the mean number of gravitons interacting with the detectors. The bipartite measurement-induced entanglement is part of the detection process, which avoids the challenges associated with developing signatures of production-induced entanglement, due to the extremely low gravitational wave detector efficiencies. The calculation of normalized measurement-induced entanglement entropy demonstrates the potential of developing physically meaningful signatures of non-classicality based on bipartite detections of gravitational radiation. This result is in stark contrast to the discouraging calculations based on single-point detections.