Carbon nanotube pendulums can prove that gravity is quantum without the need for impossible-to-build space experiments.
Proving that gravity follows the rules of quantum mechanics usually requires putting objects in perfect free-fall for a long time. This new setup uses mechanically constrained systems like tiny dangling nanotubes instead. By measuring how gravity entangles these fixed pendulums, researchers can skip the need for complex space-based interferometry. This significantly lowers the barrier to solving one of the biggest mysteries in physics. It moves the quest for quantum gravity from the realm of theory into a manageable tabletop experiment.
Gravity-induced Entanglement under Constrained Dynamics
arXiv · 2605.00967
Tests of gravity-induced entanglement have been proposed as a route to probing the quantum nature of gravity, but existing schemes rely on free-fall interferometry of massive spatial superpositions, imposing severe experimental constraints. We show that systems exhibiting effectively inertial dynamics in the short-time regime reproduce the same gravitational phase accumulation responsible for entanglement generation. Deviations from the free-fall phase enter at order $(t/T)^2$, where $t$ is the