Underground experiment finds no sign of gravity-induced decoherence

An experiment at Italy's INFN Gran Sasso underground lab found no trace of spacetime fluctuations predicted by the Károlyházy model, which would disrupt quantum superpositions. Data was collected for 62 days with a high-purity germanium detector, ruling out one of the oldest gravity-driven decoherence models.

• High-purity germanium detector collected data for 62 days under 1.4 km of rock
• No signal of spacetime fluctuations predicted by the Károlyházy model
• Result rules out one of the oldest gravity-induced decoherence models
• Findings published in New Journal of Physics in June 2026