Researchers at Bengaluru's Raman Research Institute reported an optical experiment that measured a quantum quantity of approximately 1.17. The study, published on September 24, connects an approach called Quantum Measure Theory with measurements of light travelling through several possible paths.
The team used light's polarisation to distinguish and select a collection of routes, then removed that identifying information so the routes could interfere. Measurements of incoming and outgoing laser power, combined with a calibrated filter, allowed the researchers to infer the quantum measure for that collection.
The value exceeds one because the measure includes interference between paths. It does not describe an event with a probability above 100 percent: the ordinary detection probability stays within its usual bounds. The experiment creates a way to examine whole collections of quantum histories, with potential future applications in measurement and information processing.