No signal underground: Scientists challenge a decades-old idea about how quantum reality breaks down. Schrödinger’s cat has a new problem

A deep-underground experiment in Italy has challenged a decades-old theory that gravity may destroy quantum superpositions. After 62 days of measurements at Gran Sasso, researchers found no trace of the faint radiation predicted by the model. The result does not explain why quantum behavior fades in everyday objects, but it rules out one proposed gravity-driven mechanism, giving physicists new limits in the search for an explanation of quantum decoherence.