Schrodinger's cat, both dead and alive at once, was always meant to be a thought experiment, but will ordinary objects or your favourite feline ever enter the quantum world? No one knows, but now there is a way to measure how close physicists are to realising the thought experiment.
The laws of quantum mechanics should apply to everything, from the tiniest particle to the entire universe. However, their effects are usually too small to see on everyday scales. Physicists are continually testing quantum effects at increasing scales, to probe the divide between the classical and quantum realms. But without a ranking system it wasn't clear how far they had got.
Klaus Hornberger of the University of Duisburg-Essen in Germany and his colleague Stefan Nimmrichter have come up with such a system. If a quantum-classical divide exists, quantum laws will have to change. But successful quantum experiments at larger and larger scales rule out some of the possible modifications. The more changes an experiment rules out, the higher it scores.
To read more, click here.