Quantum effects in weak gravitational fields: towards tabletop tests of quantum gravity

Abstract

This study explores quantum effects in weak gravitational fields with the aim of identifying feasible pathways towards tabletop tests of quantum gravity. Using numerical simulations of matter-wave interference for nanoparticles with masses between and  kg, we investigate how environmental and fundamental decoherence mechanisms shape observable signatures. The results reveal a mass-dependent reduction in interference visibility, dropping from near unity at  kg to below 0.2 at  kg. Coherence times were found to exceed one second for particles lighter than 10^(-16) kg under cryogenic ultra-high-vacuum conditions, but decreased to sub-millisecond scales for  kg particles at room temperature, confirming thermal radiation as the dominant source of decoherence. In parallel, collapse models such as CSL predict additional suppression of visibility for interrogation times of 0.1 s, particularly for masses above  kg, enabling discrimination between environmental and intrinsic decoherence mechanisms. These findings underscore the necessity of maintaining ultra-high vacuum and cryogenic environments to detect gravitationally induced quantum phases, thereby providing a practical framework for near-future interferometry experiments. While the present work is limited to phenomenological models and simulated data, it establishes a roadmap for extending investigations to heavier mass regimes, incorporating realistic noise sources, and testing alternative collapse scenarios.