Quantum Entanglement of Neutron Spin, Path and Energy

What does a quantum particle do when you are not looking at it? For a classical moving object, like a golf ball, we know its trajectory even when we are not looking at it. This is not the case with quantum particles, such as neutrons, whose behavior is described by quantum mechanics (QM) in terms only of probable outcomes of a measurement. Einstein argued that QM was unlikely to be a full theory because it did not comply with what he regarded as common sense (local realism). It leads to strange phenomena like entanglement of quantum states that are currently being researched as the basis for future quantum computing. Our experiment aims to confirm entanglement for neutrons. If successful, we expect to open up an important new method of probing entangled electron states in advanced materials that are expected to underpin new technologies in the computing and energy sectors.