Researchers at NIST and their colleagues have proposed an experiment that could help determine if gravity is a quantum force. The experiment would use a cold cloud of atoms trapped inside an atomic interferometer, which has two arms. A small mass suspended as a pendulum is introduced just outside the interferometer. If gravitational entanglement occurs, the position of the atom in the interferometer would be correlated with the direction the pendulum swings. This would cause the interference pattern to collapse and revive as the pendulum swings back and forth. The collapse and revival of the interference pattern would be a “smoking gun” for gravitational entanglement. While the ideal experiment may take a decade or more to build, a preliminary version could be ready in a few years with some design shortcuts.
Source: https://www.nist.gov/news-events/news/2021/08/exploring-quantum-gravity-whom-pendulum-swings
Keywords: gravitational entanglement, quantum theory, entanglement, atom interferometer, quantum state, superposition principle
