Massive quantum systems as interfaces of quantum mechanics and gravity

The authors review theories and experimental state-of-the-art efforts to study the effects of gravity on massive quantum systems. Classical gravity is the least precisely tested natural force and may be addressed via precision quantum probes. Experiments testing whether the quantum nature of gravity causes decoherence and collapse of matter-wave functions and whether it can mediate entanglement between separate massive particles are underway, and their results will guide the theoretical description of gravity effects on a laboratory scale.