Closing the last Bell-test loophole for photons

An international team of researchers has reached a milestone in experimental confirmation of a key tenet of quantum mechanics, using ultra-sensitive photon detectors devised by PML scientists.

The work, reported last month in Nature, eliminates the last remaining potential obstacle to a quantum-mechanical interpretation of results from observations of pairs of "entangled" photons. Entanglement is an exclusively quantum, non-classical phenomenon in which the properties of each photon in the pair are intrinsically correlated – no matter how far they are separated in space – but unknowable prior to the act of measurement.