# Usurping Quantum Theory

Imagine creating two quantum particles in the same place and passing one to Alice and the other to Bob to experiment on and produce a measurement. Those particles might exhibit the properties of entanglement: change the quantum state of Alice’s particle and Bob’s instantly changes too. Some of those correlations cannot be explained using everyday “classical” physics. The set of quantum correlations is actually greater than the set of classical correlations, with the latter being a particular sub-set of the former. And just as quantum theory usurped classical theory, Miguel Navascués hopes to topple quantum theory by finding an alternative that, in turn, has a greater set of correlations, but that still contains those of quantum theory within it. Three years ago he made a breakthrough. “We call it the ‘almost quantum’ set,” he says. “It contains correlations and outcomes not possible within quantum theory.”