Space-based cm/kg-scale Laser Interferometer for Quantum Gravity

TL;DR

This paper proposes a space-based laser interferometer with kg-scale test masses to detect gravitationally induced entanglement, advancing experimental quantum gravity research with feasible modifications to existing missions.

Contribution

It introduces a novel space-based interferometer design inspired by LISA Pathfinder for detecting quantum gravity effects via GIE, with detailed noise analysis and practical implementation considerations.

Findings

GIE detection is feasible with minimal modifications to LPF.

Simulated measurements show detection within reasonable integration times.

Design effectively isolates quantum gravitational signals from noise.

Abstract

The experimental verification of the quantum nature of gravity represents a milestone in quantum gravity research. Recently, interest has grown for testing it via gravitationally induced entanglement (GIE). Here, we propose a space-based interferometer inspired by the LISA Pathfinder (LPF). Our design employs two kg-scale gold-platinum test masses which, unlike in the LPF, are surrounded by a shield below 1 K and positioned side-by-side with a centimeter-scale separation. This configuration enables the detection of GIE through simultaneous measurements of differential and common-mode motions. To estimate the integration time required for GIE detection, we simulate quantum measurements of these modes, considering noise sources such as gas damping, black-body radiation, and cosmic-ray collisions. Our results show that GIE can be demonstrated with a few modifications to the LPF setup.