[gus_massa]

I agree. There are a (very) few experiments that show the effect of gravity in a system with strong quantum effects.

Fox example you can split a ray of neutrons, direct each beam through a different path with different height and then make them collide and see the interference pattern. The idea is that the split creates a superposition and each half has a different gravity potential, changing the orientation of the experiment produce different interference patterns. (The details are in the book of Sakurai "Modern Quantum Mechanics" pp127-129, with data from an experiment of Colella, Overhauser, Werner (1975).)

I don't understand why the old experiment was not enough to falsify this theory.